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Zhang J, Chen L, Xiao Y, Dai W, Yang L, Zhou L, Zou JP, Luo X, Jing G. Insight into the Alkali Resistance Mechanism of FeMoTiO x Catalysts for NH 3 Selective Catalytic Reduction of NO: Self-Defense Effects of MoO x for Alkali Capture. Environ Sci Technol 2024; 58:4145-4154. [PMID: 38381076 DOI: 10.1021/acs.est.3c08557] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/22/2024]
Abstract
The deactivation of selective catalytic reduction (SCR) catalysts caused by alkali metal poisoning remains an insurmountable challenge. In this study, we examined the impact of Na poisoning on the performance of Fe and Mo co-doped TiO2 (FeaMobTiOx) catalysts in the SCR reaction and revealed the related alkali resistance mechanism. On the obtained Fe1Mo2.6TiOx catalyst, the synergistic catalytic effect of uniformly dispersed FeOx and MoOx species leads to remarkable catalytic activity, with over 90% NO conversion achieved in a wide temperature range of 210-410 °C. During the Na poisoning process, Na ions predominantly adsorb on the MoOx species, which exhibit stronger alkali resistance, effectively safeguarding the FeOx species. This preferential adsorption minimizes the negative effect of Na poisoning on Fe1Mo2.6TiOx. Moreover, Na poisoning has little influence on the Eley-Rideal reaction pathway involving adsorbed NHx reacting with gaseous NOx. After Na poisoning, the Lewis acid sites were deteriorated, while the abundant Brønsted acid sites ensured sufficient NHx adsorption. As a benefit from the self-defense effects of active MoOx species for alkali capture, FeaMobTiOx exhibits exceptional alkali resistance in the SCR reaction. This research provides valuable insights for the design of highly efficient and alkali-resistant SCR catalysts.
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Affiliation(s)
- Jie Zhang
- Key Laboratory of Jiangxi Province for Persistent Pollutants Control and Resources Recycle, Nanchang Hangkong University, Nanchang, Jiangxi 330063, People's Republic of China
| | - Liqiu Chen
- Key Laboratory of Jiangxi Province for Persistent Pollutants Control and Resources Recycle, Nanchang Hangkong University, Nanchang, Jiangxi 330063, People's Republic of China
| | - Yuming Xiao
- Key Laboratory of Jiangxi Province for Persistent Pollutants Control and Resources Recycle, Nanchang Hangkong University, Nanchang, Jiangxi 330063, People's Republic of China
| | - Weili Dai
- Key Laboratory of Jiangxi Province for Persistent Pollutants Control and Resources Recycle, Nanchang Hangkong University, Nanchang, Jiangxi 330063, People's Republic of China
| | - Lixia Yang
- Key Laboratory of Jiangxi Province for Persistent Pollutants Control and Resources Recycle, Nanchang Hangkong University, Nanchang, Jiangxi 330063, People's Republic of China
| | - Lei Zhou
- Key Laboratory of Jiangxi Province for Persistent Pollutants Control and Resources Recycle, Nanchang Hangkong University, Nanchang, Jiangxi 330063, People's Republic of China
| | - Jian-Ping Zou
- Key Laboratory of Jiangxi Province for Persistent Pollutants Control and Resources Recycle, Nanchang Hangkong University, Nanchang, Jiangxi 330063, People's Republic of China
| | - Xubiao Luo
- Key Laboratory of Jiangxi Province for Persistent Pollutants Control and Resources Recycle, Nanchang Hangkong University, Nanchang, Jiangxi 330063, People's Republic of China
- School of Life Science, Jinggangshan University, Ji'an, Jiangxi 343009, People's Republic of China
| | - Guohua Jing
- Department of Environmental Science & Engineering, College of Chemical Engineering, Huaqiao University, Xiamen, Fujian 361021, People's Republic of China
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2
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Chen Y, Feng J, Wang X, Zhang C, Ke D, Zhu H, Wang S, Suo H, Liu C. Iterative Approach of Experiment-Machine Learning for Efficient Optimization of Environmental Catalysts: An Example of NO x Selective Reduction Catalysts. Environ Sci Technol 2023; 57:18080-18090. [PMID: 37393584 PMCID: PMC10666265 DOI: 10.1021/acs.est.3c00293] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/12/2023] [Revised: 04/01/2023] [Accepted: 06/15/2023] [Indexed: 07/04/2023]
Abstract
An iterative approach between machine learning (ML) and laboratory experiments was developed to accelerate the design and synthesis of environmental catalysts (ECs) using selective catalytic reduction (SCR) of nitrogen oxides (NOx) as an example. The main steps in the approach include training a ML model using the relevant data collected from the literature, screening candidate catalysts from the trained model, experimentally synthesizing and characterizing the candidates, updating the ML model by incorporating the new experimental results, and screening promising catalysts again with the updated model. This process is iterated with a goal to obtain an optimized catalyst. Using the iterative approach in this study, a novel SCR NOx catalyst with low cost, high activity, and a wide range of application temperatures was found and successfully synthesized after four iterations. The approach is general enough that it can be readily extended for screening and optimizing the design of other environmental catalysts and has strong implications for the discovery of other environmental materials.
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Affiliation(s)
- Yulong Chen
- State Environmental Protection
Key Laboratory of Integrated Surface Water-Groundwater Pollution Control,
School of Environmental Science and Engineering, Southern University of Science and Technology, Shenzhen, Guangdong 518055, People’s
Republic of China
| | - Jia Feng
- State Environmental Protection
Key Laboratory of Integrated Surface Water-Groundwater Pollution Control,
School of Environmental Science and Engineering, Southern University of Science and Technology, Shenzhen, Guangdong 518055, People’s
Republic of China
| | - Xin Wang
- State Environmental Protection
Key Laboratory of Integrated Surface Water-Groundwater Pollution Control,
School of Environmental Science and Engineering, Southern University of Science and Technology, Shenzhen, Guangdong 518055, People’s
Republic of China
| | - Cheng Zhang
- State Environmental Protection
Key Laboratory of Integrated Surface Water-Groundwater Pollution Control,
School of Environmental Science and Engineering, Southern University of Science and Technology, Shenzhen, Guangdong 518055, People’s
Republic of China
| | - Dongfang Ke
- State Environmental Protection
Key Laboratory of Integrated Surface Water-Groundwater Pollution Control,
School of Environmental Science and Engineering, Southern University of Science and Technology, Shenzhen, Guangdong 518055, People’s
Republic of China
| | - Huiyan Zhu
- State Environmental Protection
Key Laboratory of Integrated Surface Water-Groundwater Pollution Control,
School of Environmental Science and Engineering, Southern University of Science and Technology, Shenzhen, Guangdong 518055, People’s
Republic of China
| | - Shuai Wang
- State Environmental Protection
Key Laboratory of Integrated Surface Water-Groundwater Pollution Control,
School of Environmental Science and Engineering, Southern University of Science and Technology, Shenzhen, Guangdong 518055, People’s
Republic of China
| | - Hongri Suo
- State Environmental Protection
Key Laboratory of Integrated Surface Water-Groundwater Pollution Control,
School of Environmental Science and Engineering, Southern University of Science and Technology, Shenzhen, Guangdong 518055, People’s
Republic of China
| | - Chongxuan Liu
- State Environmental Protection
Key Laboratory of Integrated Surface Water-Groundwater Pollution Control,
School of Environmental Science and Engineering, Southern University of Science and Technology, Shenzhen, Guangdong 518055, People’s
Republic of China
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3
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Shen Z, Wang P, Hu X, Qu W, Liu X, Zhang D. Ultrahighly Alkali-Tolerant NO x Reduction over Self-Adaptive CePO 4/FePO 4 Catalysts. Environ Sci Technol 2023; 57:14472-14481. [PMID: 37695840 DOI: 10.1021/acs.est.3c05112] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 09/13/2023]
Abstract
Catalyst deactivation caused by alkali metal poisoning has long been a key bottleneck in the application of selective catalytic reduction of NOx with NH3 (NH3-SCR), limiting the service life of the catalyst and increasing the cost of environmental protection. Despite great efforts, continuous accumulation of alkali metal deposition makes the resistance capacity of 2 wt % K2O difficult to enhance via merely loading acid sites on the surface, resulting in rapid deactivation and frequent replacement of the NH3-SCR catalyst. To further improve the resistance of alkali metals, encapsulating alkali metals into the bulk phase could be a promising strategy. The bottleneck of 2 wt % K2O tolerance has been solved by virtue of ultrahigh potassium storage capacity in the amorphous FePO4 bulk phase. Amorphous FePO4 as a support of the NH3-SCR catalyst exhibited a self-adaptive alkali-tolerance mechanism, where potassium ions spontaneously migrated into the bulk phase of amorphous FePO4 and were anchored by PO43- with the generation of Fe2O3 at the NH3-SCR reaction temperature. This ingenious potassium storage mechanism could boost the K2O resistance capacity to 6 wt % while maintaining approximately 81% NOx conversion. Besides, amorphous FePO4 also exhibited excellent resistance to individual and coexistence of alkali (K2O and Na2O), alkali earth (CaO), and heavy metals (PbO and CdO), providing long durability for CePO4/FePO4 catalysts in flue gas with multipollutants. The cheap and accessible amorphous FePO4 paves the way for the development and implementation of poisoning-resistant NOx abatement.
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Affiliation(s)
- Zhi Shen
- State Key Laboratory of Advanced Special Steel, School of Materials Science and Engineering, International Joint Laboratory of Catalytic Chemistry, College of Sciences, Shanghai University, Shanghai 200444, China
| | - Penglu Wang
- State Key Laboratory of Advanced Special Steel, School of Materials Science and Engineering, International Joint Laboratory of Catalytic Chemistry, College of Sciences, Shanghai University, Shanghai 200444, China
| | - Xiaonan Hu
- State Key Laboratory of Advanced Special Steel, School of Materials Science and Engineering, International Joint Laboratory of Catalytic Chemistry, College of Sciences, Shanghai University, Shanghai 200444, China
| | - Wenqiang Qu
- State Key Laboratory of Advanced Special Steel, School of Materials Science and Engineering, International Joint Laboratory of Catalytic Chemistry, College of Sciences, Shanghai University, Shanghai 200444, China
| | - Xiangyu Liu
- State Key Laboratory of Advanced Special Steel, School of Materials Science and Engineering, International Joint Laboratory of Catalytic Chemistry, College of Sciences, Shanghai University, Shanghai 200444, China
| | - Dengsong Zhang
- State Key Laboratory of Advanced Special Steel, School of Materials Science and Engineering, International Joint Laboratory of Catalytic Chemistry, College of Sciences, Shanghai University, Shanghai 200444, China
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4
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Yuan X, Peng Y, Zhu X, Wang H, Song Z, Si W, Wang Y, Li J. Anti-Poisoning Mechanisms of Sb on Vanadia-Based Catalysts for NO x and Chlorobenzene Multi-Pollutant Control. Environ Sci Technol 2023. [PMID: 37427417 DOI: 10.1021/acs.est.3c02844] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Subscribe] [Scholar Register] [Indexed: 07/11/2023]
Abstract
Modulating vanadia-based metal oxides is one of the effective methods for designing difunctional catalysts for simultaneous control of NOx and chlorobenzene (CB) from the emissions of industrial sources. Excessive NH3 adsorption and polychlorinated species accumulation on the surface are the primary issues poisoning catalysts and reducing their lifetime. Herein, Sb is selected as an NH3 adsorption alleviator and polychlorinated species preventor dopant on V2O5-WO3/TiO2. The catalyst exhibits an excellent performance for total NOx and 90% CB conversions at 300-400 °C under a gas hourly space velocity (GHSV) of 60,000 mL g-1 h-1. The HCl and N2 selectivities are maintained at 90 and 98%, respectively. The anti-poisoning ability could be attributed to the generated V-O-Sb chains on the surface: the band gap of vanadium is narrowed and the electron capability is strengthened. The above variation weakens the Lewis acid sites and blocks the electrophilic chlorination reactions of the catalyst surface (formation of polychlorinated species). In addition, oxygen vacancies on Sb-O-Ti also increase: the ring opening of benzoates is accelerated and NH3 adsorption energy is weakened. The above variation lowers the energy barriers of C-Cl cleavage even under NH3 pre-adsorption models and enhances NOx reduction thermodynamically and kinetically.
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Affiliation(s)
- Xing Yuan
- State Key Joint Laboratory of Environment Simulation and Pollution Control, School of Environment, Tsinghua University, Beijing 100084, China
| | - Yue Peng
- State Key Joint Laboratory of Environment Simulation and Pollution Control, School of Environment, Tsinghua University, Beijing 100084, China
| | - Xiao Zhu
- State Key Joint Laboratory of Environment Simulation and Pollution Control, School of Environment, Tsinghua University, Beijing 100084, China
| | - Houlin Wang
- State Key Joint Laboratory of Environment Simulation and Pollution Control, School of Environment, Tsinghua University, Beijing 100084, China
| | - Zijian Song
- China National Institute of Standardization, Beijing 100191, China
| | - Wenzhe Si
- State Key Joint Laboratory of Environment Simulation and Pollution Control, School of Environment, Tsinghua University, Beijing 100084, China
| | - Yu Wang
- School of Environmental Science and Engineering, Yancheng Institute of Technology, Yancheng 224051, China
| | - Junhua Li
- State Key Joint Laboratory of Environment Simulation and Pollution Control, School of Environment, Tsinghua University, Beijing 100084, China
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5
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Qu W, Fang X, Ren Z, Chen J, Liu X, Ma Z, Tang X. NO Selective Catalytic Reduction over Atom-Pair Active Sites Accelerated via In Situ NO Oxidation. Environ Sci Technol 2023; 57:7858-7866. [PMID: 37161886 DOI: 10.1021/acs.est.3c00461] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/11/2023]
Abstract
Selective catalytic reduction (SCR) of NOx with NH3 is the most efficient technology for NOx emissions control, but the activity of catalysts decreases exponentially with the decrease in reaction temperature, hindering the application of the technology in low-temperature SCR to treat industrial stack gases. Here, we present an industrially practicable technology to significantly enhance the SCR activity at low temperatures (<250 °C). By introducing an appropriate amount of O3 into the simulated stack gas, we find that O3 can stoichiometrically oxidize NO to generate NO2, which enables NO reduction to follow the fast SCR mechanism so as to accelerate SCR at low temperatures, and, in particular, an increase in SCR rate by more than four times is observed over atom-pair V1-W1 active sites supported on TiO2(001) at 200 °C. Using operando SCR tests and in situ diffuse reflectance infrared Fourier transform spectra, we reveal that the introduction of O3 allows SCR to proceed along a NH4NO3-mediated Langmuir-Hinshelwood model, in which the adsorbed nitrate species speed up the re-oxidation of the catalytic sites that is the rate-limiting step of SCR, thus leading to the enhancement of activity at low temperatures. This technology could be applicable in the real stack gas conditions because O3 exclusively oxidizes NO even in the co-presence of SO2 and H2O, which provides a general strategy to improve low-temperature SCR efficacy from another perspective beyond designing catalysts.
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Affiliation(s)
- Weiye Qu
- Department of Environmental Science & Engineering, Fudan University, Shanghai 200433, China
| | - Xue Fang
- Department of Environmental Science & Engineering, Fudan University, Shanghai 200433, China
| | - Zhouhong Ren
- School of Chemistry and Chemical Engineering, In-situ Center for Physical Sciences, Shanghai Jiao Tong University, Shanghai 200240, China
| | - Junxiao Chen
- Department of Environmental Science & Engineering, Fudan University, Shanghai 200433, China
| | - Xi Liu
- School of Chemistry and Chemical Engineering, In-situ Center for Physical Sciences, Shanghai Jiao Tong University, Shanghai 200240, China
| | - Zhen Ma
- Department of Environmental Science & Engineering, Fudan University, Shanghai 200433, China
- Shanghai Institute of Pollution Control and Ecological Security, Shanghai 200092, China
| | - Xingfu Tang
- Department of Environmental Science & Engineering, Fudan University, Shanghai 200433, China
- Jiangsu Collaborative Innovation Center of Atmospheric Environment & Equipment Technology, Nanjing University of Information Science & Technology, Nanjing 210044, China
- Shanghai Institute of Pollution Control and Ecological Security, Shanghai 200092, China
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6
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Wang Y, Chen L, Wang W, Wang X, Li B, Zhang S, Li W, Li S. Revealing the Excellent Low-Temperature Activity of the Fe 1-xCe xO δ-S Catalyst for NH 3-SCR: Improvement of the Lattice Oxygen Mobility. ACS Appl Mater Interfaces 2023; 15:17834-17847. [PMID: 37000486 DOI: 10.1021/acsami.3c00212] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/19/2023]
Abstract
The development of selective catalytic reduction catalysts by NH3(NH3-SCR) with excellent low-temperature activity and a wide temperature window is highly demanded but is still very challenging for the elimination of NOx emission from vehicle exhaust. Herein, a series of sulfated modified iron-cerium composite oxide Fe1-xCexOδ-S catalysts were synthesized. Among them, the Fe0.79Ce0.21Oδ-S catalyst achieved the highest NOx conversion of more than 80% at temperatures of 175-375 °C under a gas hourly space velocity of 100000 h-1. Sulfation formed a large amount of sulfate on the surface of the catalyst and provided rich Brønsted acid sites, thus enhancing its NH3 adsorption capacity and improving the overall NOx conversion efficiency. The introduction of Ce is the main determining factor in regulating the low-temperature activity of the catalyst by modulating its redox ability. Further investigation found that there is a strong interaction between Fe and Ce, which changed the electron density around the Fe ions in the Fe0.79Ce0.21Oδ-S catalyst. This weakened the strength of the Fe-O bond and improved the lattice oxygen mobility of the catalyst. During the reaction, the iron-cerium composite oxide catalyst showed higher surface lattice oxygen activity and a faster replenishment rate of bulk lattice oxygen. This significantly improved the adsorption and activation of NOx species and the activation of NH3 species on the catalyst surface, thus leading to the superior low-temperature activity of the catalyst.
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Affiliation(s)
- Yaqing Wang
- Key Laboratory of Biomass Chemical Engineering of Ministry of Education, Institute of Industrial Ecology and Environment, College of Chemical and Biological Engineering, Zhejiang University, Hangzhou 310027, China
| | - Liang Chen
- Key Laboratory of Biomass Chemical Engineering of Ministry of Education, Institute of Industrial Ecology and Environment, College of Chemical and Biological Engineering, Zhejiang University, Hangzhou 310027, China
- Key Laboratory of Organosilicon Chemistry and Material Technology, Ministry of Education, College of Material, Chemistry and Chemical Engineering, Hangzhou Normal University, Hangzhou 311121, Zhejiang, P. R. China
| | - Weijia Wang
- Key Laboratory of Biomass Chemical Engineering of Ministry of Education, Institute of Industrial Ecology and Environment, College of Chemical and Biological Engineering, Zhejiang University, Hangzhou 310027, China
| | - Xiaoxiang Wang
- Key Laboratory of Biomass Chemical Engineering of Ministry of Education, Institute of Industrial Ecology and Environment, College of Chemical and Biological Engineering, Zhejiang University, Hangzhou 310027, China
| | - Beilei Li
- Key Laboratory of Biomass Chemical Engineering of Ministry of Education, Institute of Industrial Ecology and Environment, College of Chemical and Biological Engineering, Zhejiang University, Hangzhou 310027, China
| | - Shihan Zhang
- Key Laboratory of Microbial Technology for Industrial Pollution Control of Zhejiang Province, College of Environment, Zhejiang University of Technology, Hangzhou 310014, China
| | - Wei Li
- Key Laboratory of Biomass Chemical Engineering of Ministry of Education, Institute of Industrial Ecology and Environment, College of Chemical and Biological Engineering, Zhejiang University, Hangzhou 310027, China
| | - Sujing Li
- Key Laboratory of Biomass Chemical Engineering of Ministry of Education, Institute of Industrial Ecology and Environment, College of Chemical and Biological Engineering, Zhejiang University, Hangzhou 310027, China
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Huang W, Wang L, Dong L, Hu H, Ren D. Density Functional Study on Adsorption of NH(3) and NO(x) on the γ-Fe(2)O(3) (111) Surface. Molecules 2023; 28. [PMID: 36903617 DOI: 10.3390/molecules28052371] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2023] [Revised: 02/26/2023] [Accepted: 03/01/2023] [Indexed: 03/08/2023] Open
Abstract
γ-Fe2O3 is considered to be a promising catalyst for the selective catalytic reduction (SCR) of nitrogen oxide (NOx). In this study, first-principle calculations based on the density function theory (DFT) were utilized to explore the adsorption mechanism of NH3, NO, and other molecules on γ-Fe2O3, which is identified as a crucial step in the SCR process to eliminate NOx from coal-fired flue gas. The adsorption characteristics of reactants (NH3 and NOx) and products (N2 and H2O) at different active sites of the γ-Fe2O3 (111) surface were investigated. The results show that the NH3 was preferably adsorbed on the octahedral Fe site, with the N atom bonding to the octahedral Fe site. Both octahedral and tetrahedral Fe atoms were likely involved in bonding with the N and O atoms during the NO adsorption. The NO tended to be adsorbed on the tetrahedral Fe site though the combination of the N atom and the Fe site. Meanwhile, the simultaneous bonding of N and O atoms with surface sites made the adsorption more stable than that of single atom bonding. The γ-Fe2O3 (111) surface exhibited a low adsorption energy for N2 and H2O, suggesting that they could be adsorbed onto the surface but were readily desorbed, thus facilitating the SCR reaction. This work is conducive to reveal the reaction mechanism of SCR on γ-Fe2O3 and contributes to the development of low-temperature iron-based SCR catalysts.
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Zhu N, Hong Y, Qian F, Xu X. Kinetic Model of Urea-Related Deposit Reactions. Molecules 2023; 28. [PMID: 36903585 DOI: 10.3390/molecules28052340] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2023] [Revised: 02/27/2023] [Accepted: 03/01/2023] [Indexed: 03/06/2023] Open
Abstract
The thermal analysis kinetic method was employed to solve the activation energies of the thermal decomposition reactions of urea and cyanuric acid, with the purpose of understanding the formation of deposits in the diesel engine SCR system. The deposit reaction kinetic model was established by optimizing the reaction paths and reaction kinetic parameters based on the thermal analysis test data of the key components in the deposit. The result shows that the established deposit reaction kinetic model can accurately describe the decomposition process of the key components in the deposit. Compared to the Ebrahimian model, the simulation precision of the established deposit reaction kinetic model is significantly improved above 600 K. The activation energies of the urea and cyanuric acid decomposition reactions are 84 kJ/mol and 152 kJ/mol, respectively, after model parameters identification. The identified activation energies were closest to those of the Friedman one-interval method indicating that the Friedman one-interval method is reasonable to solve the activation energies of deposit reactions.
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Chen G, Chen J, Chen X, Yin R, Li K, Li J. Monolith or Powder: Improper Sample Pretreatment May Mislead the Understanding of Industrial V 2O 5-WO 3/TiO 2 Catalysts Operated in Stationary Resources. Environ Sci Technol 2022; 56:16394-16399. [PMID: 36261232 DOI: 10.1021/acs.est.2c05022] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/16/2023]
Abstract
Although various characterizations are widely applied to commercial V2O5-WO3/TiO2 catalysts, the influence of the catalyst physical structure, i.e., monolith or powder, on the characterization results has not been investigated. Several important catalytic behaviors and phenomena were observed in this study using V2O5-WO3/TiO2 monolithic catalysts employed for over 5000 h in various stationary flue gases, and many of the results were only observable on monolithic catalysts, such as depth-dependent distribution of external elements, penetration of As2O3, and the formation of Tl2O-TiO2 p-n junctions. If the monolith is ground into powder states, it will alter or destroy the catalyst surface and remove important clues closely related to catalytic performance under working conditions. The redox and acidity properties of V2O5-WO3/TiO2 obtained from powder samples may be significantly different from their true state under working conditions, resulting in a misperception of catalyst performance. Therefore, a cautious pretreatment should be taken into careful consideration when analyzing commercial honeycomb V2O5-WO3/TiO2 catalysts.
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Affiliation(s)
- Gongda Chen
- State Key Joint Laboratory of Environment Simulation and Pollution Control, School of Environment, Tsinghua University, Beijing 100084, PR China
- New Technology Center, Guangdong Energy Group Science and Technology Research Institute Co., Ltd., Guangzhou 510630, PR China
| | - Jianjun Chen
- State Key Joint Laboratory of Environment Simulation and Pollution Control, School of Environment, Tsinghua University, Beijing 100084, PR China
| | - Xiaoping Chen
- State Key Joint Laboratory of Environment Simulation and Pollution Control, School of Environment, Tsinghua University, Beijing 100084, PR China
| | - Rongqiang Yin
- State Key Joint Laboratory of Environment Simulation and Pollution Control, School of Environment, Tsinghua University, Beijing 100084, PR China
| | - Kezhi Li
- Institute of Engineering Technology, Sinopec Catalyst Co., Ltd., Beijing 100029, PR China
| | - Junhua Li
- State Key Joint Laboratory of Environment Simulation and Pollution Control, School of Environment, Tsinghua University, Beijing 100084, PR China
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Li Z, Chen G, Shao Z, Zhang H, Guo X. The Effect of Iron Content on the Ammonia Selective Catalytic Reduction Reaction (NH 3-SCR) Catalytic Performance of FeO x/SAPO-34. Int J Environ Res Public Health 2022; 19:14749. [PMID: 36429468 PMCID: PMC9691003 DOI: 10.3390/ijerph192214749] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 10/13/2022] [Revised: 11/02/2022] [Accepted: 11/04/2022] [Indexed: 06/16/2023]
Abstract
Iron-based catalysts are regarded as promising candidates for the ammonia selective catalytic reduction reaction (NH3-SCR) which show good catalytic activity at medium and high temperatures, whereas SAPO-34 molecular sieves have a micro-pore structure and are ideal catalyst carriers. In this paper, four FeOx/SAPO-34 molecular sieve catalysts with different iron contents (Fe = 1%, 2%, 3%, 4%) were prepared using an impregnation method. The effect of iron content on the surface properties and catalytic activity was investigated by a series of characterization techniques including XRD, SEM, BET, XPS, H2-TPR and NH3-TPD. Iron species in the FeOx/SAPO-34 catalysts exist in the form of isolated iron ions or well-dispersed small crystals and iron oxide species clusters. With the addition of iron content, the integrity of CHA (chabazite) zeolite structure remained, but the crystallinity was affected. The FeOx/SAPO-34 catalyst with 3% Fe loading showed a relatively flat surface with no large-diameter particles and strong oxidation-reduction ability. Meanwhile, more acidic sites are exposed, which accelerated the process of catalytic reaction. Thus, the FeOx/SAPO-34 catalyst with 3% Fe showed the best NO conversion performance among the four catalysts prepared and maintained more than 90% NO conversion efficiency in a wide temperature range from 310 °C to 450 °C.
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Affiliation(s)
- Zhaoyang Li
- Faculty of Maritime and Transportation, Ningbo University, Ningbo 315211, China
| | - Geng Chen
- Faculty of Maritime and Transportation, Ningbo University, Ningbo 315211, China
| | - Zhenghua Shao
- Faculty of Maritime and Transportation, Ningbo University, Ningbo 315211, China
| | - Haonan Zhang
- Faculty of Maritime and Transportation, Ningbo University, Ningbo 315211, China
| | - Xiujuan Guo
- School of Civil and Transportation Engineering, Ningbo University of Technology, Ningbo 315211, China
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Zou J, Impeng S, Wang F, Lan T, Wang L, Wang P, Zhang D. Compensation or Aggravation: Pb and SO 2 Copoisoning Effects over Ceria-Based Catalysts for NO x Reduction. Environ Sci Technol 2022; 56:13368-13378. [PMID: 36074097 DOI: 10.1021/acs.est.2c03653] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/15/2023]
Abstract
Severe catalyst deactivation caused by multiple poisons, including heavy metals and SO2, remains an obstinate issue for the selective catalytic reduction (SCR) of NOx by NH3. The copoisoning effects of heavy metals and SO2 are still unclear and irreconcilable. Herein, the unanticipated differential compensated or aggravated Pb and SO2 copoisoning effects over ceria-based catalysts for NOx reduction was originally unraveled. It was demonstrated that Pb and SO2 exhibited a compensated copoisoning effect over the CeO2/TiO2 (CT) catalyst with sole active CeO2 sites but an aggravated copoisoning effect over the CeO2-WO3/TiO2 (CWT) catalyst with dual active CeO2 sites and acidic WO3 sites. Furthermore, it was uniquely revealed that Pb preferred bonding with CeO2 among CT while further being combined with SO2 to form PbSO4 after copoisoning, which released the poisoned active CeO2 sites and rendered the copoisoned CT catalyst a recovered reactivity. In comparison, Pb and SO2 would poison acidic WO3 sites and active CeO2 sites, respectively, resulting in a seriously degraded reactivity of the copoisoned CWT catalyst. Therefore, this work thoroughly illustrates the internal mechanism of differential compensated or aggravated deactivation effects for Pb and SO2 copoisoning over CT and CWT catalysts and provides effective solutions to design ceria-based SCR catalysts with remarkable copoisoning resistance for the coexistence of heavy metals and SO2.
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Affiliation(s)
- Jingjing Zou
- International Joint Laboratory of Catalytic Chemistry, Department of Chemistry, Research Center of Nanoscience and Technology, College of Sciences, Shanghai University, Shanghai 200444, China
| | - Sarawoot Impeng
- National Nanotechnology Center, National Science and Technology Development Agency, Pathum Thani 12120, Thailand
| | - Fuli Wang
- International Joint Laboratory of Catalytic Chemistry, Department of Chemistry, Research Center of Nanoscience and Technology, College of Sciences, Shanghai University, Shanghai 200444, China
| | - Tianwei Lan
- International Joint Laboratory of Catalytic Chemistry, Department of Chemistry, Research Center of Nanoscience and Technology, College of Sciences, Shanghai University, Shanghai 200444, China
| | - Lulu Wang
- International Joint Laboratory of Catalytic Chemistry, Department of Chemistry, Research Center of Nanoscience and Technology, College of Sciences, Shanghai University, Shanghai 200444, China
| | - Penglu Wang
- International Joint Laboratory of Catalytic Chemistry, Department of Chemistry, Research Center of Nanoscience and Technology, College of Sciences, Shanghai University, Shanghai 200444, China
| | - Dengsong Zhang
- International Joint Laboratory of Catalytic Chemistry, Department of Chemistry, Research Center of Nanoscience and Technology, College of Sciences, Shanghai University, Shanghai 200444, China
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12
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Baltrėnas P, Urbanas D, Sukackienė Z, Stalnionienė I, Tamašauskaitė-Tamašiūnaitė L, Balčiūnaitė A, Jasulaitienė V. Selective catalytic reduction of NO by NH 3 using Mn-based catalysts supported by Ukrainian clinoptiolite and lightweight expanded clay aggregate. Environ Technol 2022; 43:3269-3282. [PMID: 33881966 DOI: 10.1080/09593330.2021.1921046] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/24/2020] [Accepted: 04/16/2021] [Indexed: 06/12/2023]
Abstract
In this study, Mn-based multicomponent catalysts supported by two different carriers (lightweight expanded clay aggregate and the Ukrainian clinoptiolite) were prepared by electroless metal deposition method and tested for the selective catalytic reduction of NO with ammonia (NH3-SCR de-NO). Prior to the activity test, all the catalysts prepared were characterized by inductively coupled plasma optical emission spectroscopy, field emission scanning electron microscopy (FESEM), energy dispersive X-ray mapping, X-ray photoelectron spectroscopy, H2-TPR and NH3-TPD techniques. The particular interest of the present study was focused on the investigation of the carrier's role in the NO catalytic reduction and the promoting effect provided by the incorporation of the small amount of Pt (0.1 wt.%) in the Mn-based catalytic layer. The results revealed that the carrier's role in the NO catalytic conversion can be considered as a factor determining the effectiveness of the conversion process. Ukrainian clinoptiolite was proved to be a more attractive carrier for the preparation of the effective SCR de-NO catalysts due to its intrinsic sorption capacity, surface acidity and the redox potential. The high NO conversion efficiency provided by the Mn-based clinoptiolite-supported catalysts can be explained by the synergistic effect between the carrier and the active species deposited. It was shown that both the Mn97.6Cu2.4/clinoptiolite and the Mn97.5Co2.5/clinoptiolite catalysts can be successfully applied as the low-temperature (100-300°C) catalysts for NH3-SCR de-NO. When the NO removal efficiency varies in the range of 86-91%, the additional incorporation of Pt in the active layer in the amount of 0.1 wt.% can enhance the NO reduction by about 5% on average.
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Affiliation(s)
- Pranas Baltrėnas
- Faculty of Environmental Engineering, Vilnius Gediminas Technical University, Vilnius, Lithuania
| | - Davyd Urbanas
- Faculty of Environmental Engineering, Vilnius Gediminas Technical University, Vilnius, Lithuania
| | - Zita Sukackienė
- Center for Physical Sciences and Technology Vilnius, Lithuania
| | | | | | | | - Vitalija Jasulaitienė
- Faculty of Environmental Engineering, Vilnius Gediminas Technical University, Vilnius, Lithuania
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13
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Liu X, Wang P, Shen Y, Zheng L, Han L, Deng J, Zhang J, Wang A, Ren W, Gao F, Zhang D. Boosting SO 2-Resistant NO x Reduction by Modulating Electronic Interaction of Short-Range Fe-O Coordination over Fe 2O 3/TiO 2 Catalysts. Environ Sci Technol 2022; 56:11646-11656. [PMID: 35876848 DOI: 10.1021/acs.est.2c01812] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/15/2023]
Abstract
SO2-resistant selective catalytic reduction (SCR) of NOx remains a grand challenge for eliminating NOx generated from stationary combustion processes. Herein, SO2-resistant NOx reduction has been boosted by modulating electronic interaction of short-range Fe-O coordination over Fe2O3/TiO2 catalysts. We report a remarkable SO2-tolerant Fe2O3/TiO2 catalyst using sulfur-doped TiO2 as the support. Via an array of spectroscopic and microscopic characterizations and DFT theoretical calculations, the active form of the dopant is demonstrated as SO42- residing at subsurface TiO6 locations. Sulfur doping exerts strong electronic perturbation to TiO2, causing a net charge transfer from Fe2O3 to TiO2 via increased short-range Fe-O coordination. This electronic effect simultaneously weakens charge transfer from Fe2O3 to SO2 and enhances that from NO/NH3 to Fe2O3, resulting in a remarkable "killing two birds with one stone" scenario, that is, improving NO/NH3 adsorption that benefits SCR reaction and inhibiting SO2 poisoning that benefits catalyst long-term stability.
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Affiliation(s)
- Xiangyu Liu
- International Joint Laboratory of Catalytic Chemistry, College of Sciences, Shanghai University, Shanghai 200444, China
| | - Penglu Wang
- International Joint Laboratory of Catalytic Chemistry, College of Sciences, Shanghai University, Shanghai 200444, China
| | - Yongjie Shen
- International Joint Laboratory of Catalytic Chemistry, College of Sciences, Shanghai University, Shanghai 200444, China
| | - Lirong Zheng
- Beijing Synchrotron Radiation Facility, Institute of High Energy Physics, Chinese Academy of Sciences, Beijing 100049, China
| | - Lupeng Han
- International Joint Laboratory of Catalytic Chemistry, College of Sciences, Shanghai University, Shanghai 200444, China
| | - Jiang Deng
- International Joint Laboratory of Catalytic Chemistry, College of Sciences, Shanghai University, Shanghai 200444, China
| | - Jianping Zhang
- International Joint Laboratory of Catalytic Chemistry, College of Sciences, Shanghai University, Shanghai 200444, China
| | - Aiyong Wang
- International Joint Laboratory of Catalytic Chemistry, College of Sciences, Shanghai University, Shanghai 200444, China
| | - Wei Ren
- International Joint Laboratory of Catalytic Chemistry, College of Sciences, Shanghai University, Shanghai 200444, China
| | - Feng Gao
- Institute for Integrated Catalysis, Pacific Northwest National Laboratory, P.O. Box 999, Richland, Washington 99354, United States
| | - Dengsong Zhang
- International Joint Laboratory of Catalytic Chemistry, College of Sciences, Shanghai University, Shanghai 200444, China
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14
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Li S, Zheng Z, Zhao Z, Wang Y, Yao Y, Liu Y, Zhang J, Zhang Z. CeO 2 Nanoparticle-Loaded MnO 2 Nanoflowers for Selective Catalytic Reduction of NO x with NH 3 at Low Temperatures. Molecules 2022; 27:molecules27154863. [PMID: 35956809 PMCID: PMC9369832 DOI: 10.3390/molecules27154863] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/08/2022] [Revised: 07/26/2022] [Accepted: 07/27/2022] [Indexed: 11/16/2022] Open
Abstract
CeO2 nanoparticle-loaded MnO2 nanoflowers, prepared by a hydrothermal method followed by an adsorption-calcination technique, were utilized for selective catalytic reduction (SCR) of NOx with NH3 at low temperatures. The effects of Ce/Mn ratio and thermal calcination temperature on the NH3-SCR activity of the CeO2-MnO2 nanocomposites were studied comprehensively. The as-prepared CeO2-MnO2 catalysts show high NOx reduction efficiency in the temperature range of 150-300 °C, with a complete NOx conversion at 200 °C for the optimal sample. The excellent NH3-SCR performance could be ascribed to high surface area, intimate contact, and strong synergistic interaction between CeO2 nanoparticles and MnO2 nanoflowers of the well-designed composite catalyst. The in situ diffuse reflectance infrared Fourier transform spectroscopy (DRIFTs) characterizations evidence that the SCR reaction on the surface of the CeO2-MnO2 nanocomposites mainly follows the Langmuir-Hinshelwood (L-H) mechanism. Our work provides useful guidance for the development of composite oxide-based low temperature NH3-SCR catalysts.
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Affiliation(s)
- Shun Li
- Institute of Quantum and Sustainable Technology (IQST), School of Chemistry and Chemical Engineering, Jiangsu University, Zhenjiang 212013, China;
| | - Zuquan Zheng
- Guangdong Provincial Key Laboratory of Soil and Groundwater Pollution Control, School of Environmental Science and Engineering, Southern University of Science and Technology, Shenzhen 518055, China;
| | - Zhicheng Zhao
- Foshan (Southern China) Institute for New Materials, Foshan 528200, China; (Z.Z.); (Y.Y.)
| | - Youling Wang
- Shunde Graduate School, University of Science and Technology Beijing, Foshan 528399, China;
| | - Yao Yao
- Foshan (Southern China) Institute for New Materials, Foshan 528200, China; (Z.Z.); (Y.Y.)
| | - Yong Liu
- Foshan (Southern China) Institute for New Materials, Foshan 528200, China; (Z.Z.); (Y.Y.)
- Correspondence: (Y.L.); (J.Z.); (Z.Z.)
| | - Jianming Zhang
- Institute of Quantum and Sustainable Technology (IQST), School of Chemistry and Chemical Engineering, Jiangsu University, Zhenjiang 212013, China;
- Correspondence: (Y.L.); (J.Z.); (Z.Z.)
| | - Zuotai Zhang
- Guangdong Provincial Key Laboratory of Soil and Groundwater Pollution Control, School of Environmental Science and Engineering, Southern University of Science and Technology, Shenzhen 518055, China;
- Correspondence: (Y.L.); (J.Z.); (Z.Z.)
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15
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Sugrue RA, Preble CV, Tarplin AG, Kirchstetter TW. In-Use Passenger Vessel Emission Rates of Black Carbon and Nitrogen Oxides. Environ Sci Technol 2022; 56:7679-7686. [PMID: 35584102 DOI: 10.1021/acs.est.2c00435] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/15/2023]
Abstract
This study quantified emission factors of black carbon (BC) and nitrogen oxides (NOx) from 21 engines on in-use excursion vessels and ferries operating in California's San Francisco Bay, including EPA uncertified and Tier 1-4 engines and across engine operating modes. On average, ∼60 fuel-based emission factors per engine were measured using a novel combination of exhaust plume capture combined with GPS location and speed data that can be more readily deployed than common portable emissions measurement systems. BC and NOx emission factors (g kg-1) were lowest and least variable during fast cruising and highest during maneuvering and docked operation. Selective catalytic reduction (SCR) reduced NOx emissions by ∼80% when functional. However, elevated NOx emissions that exceeded corresponding exhaust standards were measured on most Tier 3 and Tier 4 engines sampled, which can be attributed to inactive SCR during frequent low engine load operation. In contrast, BC emissions exceeded the PM emission standard for only one engine, and SCR systems employed as a NOx reduction technology also reduced emitted BC. Using these measured emission factors to compare commuting options, we show that the CO2-equivalent emissions per passenger-kilometer are comparable when commuting by car and ferry, but BC and NOx emissions can be several to more than ten times larger when commuting by ferry.
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Affiliation(s)
- Rebecca A Sugrue
- Department of Civil and Environmental Engineering, University of California, Berkeley, Berkeley, California 94720, United States
- Energy Technologies Area, Lawrence Berkeley National Laboratory, Berkeley, California 94720, United States
| | - Chelsea V Preble
- Department of Civil and Environmental Engineering, University of California, Berkeley, Berkeley, California 94720, United States
- Energy Technologies Area, Lawrence Berkeley National Laboratory, Berkeley, California 94720, United States
| | - Anna G Tarplin
- Department of Civil and Environmental Engineering, University of California, Berkeley, Berkeley, California 94720, United States
- Energy Technologies Area, Lawrence Berkeley National Laboratory, Berkeley, California 94720, United States
| | - Thomas W Kirchstetter
- Department of Civil and Environmental Engineering, University of California, Berkeley, Berkeley, California 94720, United States
- Energy Technologies Area, Lawrence Berkeley National Laboratory, Berkeley, California 94720, United States
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16
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Zhou J, Wang P, Chen A, Qu W, Zhao Y, Zhang D. NO x Reduction over Smart Catalysts with Self-Created Targeted Antipoisoning Sites. Environ Sci Technol 2022; 56:6668-6677. [PMID: 35500206 DOI: 10.1021/acs.est.2c00758] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/14/2023]
Abstract
Selective catalytic reduction of NOx in the presence of alkali (earth) metals and heavy metals is still a challenge due to the easy deactivation of catalysts. Herein, NOx reduction over smart catalysts with self-created targeted antipoisoning sites is originally demonstrated. The smart catalyst consisted of TiO2 pillared montmorillonite with abundant cation exchange sites to anchor poisoning substances and active components to catalyze NOx into N2. It was not deactivated during the NOx reduction process in the presence of alkali (earth) metals and heavy metals. The enhanced surface acidity, reducible active species, and active chemisorbed oxygen species of the smart catalyst accounted for the remarkable NOx reduction efficiency. More importantly, the self-created targeted antipoisoning sites expressed specific anchoring effects on poisoning substances and protected the active components from poisoning. It was demonstrated that the tetrahedrally coordinated aluminum species of the smart catalyst mainly acted as self-created targeted antipoisoning sites to stabilize the poisoning substances into the interlayers of montmorillonite. This work paves a new way for efficient reduction of NOx from the complex flue gas in practical applications.
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Affiliation(s)
- Jialun Zhou
- International Joint Laboratory of Catalytic Chemistry, College of Sciences, Shanghai University, Shanghai 200444, China
| | - Penglu Wang
- International Joint Laboratory of Catalytic Chemistry, College of Sciences, Shanghai University, Shanghai 200444, China
| | - Aling Chen
- International Joint Laboratory of Catalytic Chemistry, College of Sciences, Shanghai University, Shanghai 200444, China
| | - Wenqiang Qu
- International Joint Laboratory of Catalytic Chemistry, College of Sciences, Shanghai University, Shanghai 200444, China
| | - Yufei Zhao
- International Joint Laboratory of Catalytic Chemistry, College of Sciences, Shanghai University, Shanghai 200444, China
| | - Dengsong Zhang
- International Joint Laboratory of Catalytic Chemistry, College of Sciences, Shanghai University, Shanghai 200444, China
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17
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Qi X, Han L, Deng J, Lan T, Wang F, Shi L, Zhang D. SO 2-Tolerant Catalytic Reduction of NO x via Tailoring Electron Transfer between Surface Iron Sulfate and Subsurface Ceria. Environ Sci Technol 2022; 56:5840-5848. [PMID: 35446019 DOI: 10.1021/acs.est.2c00944] [Citation(s) in RCA: 11] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/14/2023]
Abstract
Currently, SO2-induced catalyst deactivation from the sulfation of active sites turns to be an intractable issue for selective catalytic reduction (SCR) of NOx with NH3 at low temperatures. Herein, SO2-tolerant NOx reduction has been originally demonstrated via tailoring the electron transfer between surface iron sulfate and subsurface ceria. Engineered from the atomic layer deposition followed by the pre-sulfation method, the structure of surface iron sulfate and subsurface ceria was successfully constructed on CeO2/TiO2 catalysts, which delivered improved SO2 resistance for NOx reduction at 250 °C. It was demonstrated that the surface iron sulfate inhibited the sulfation of subsurface Ce species, while the electron transfer from the surface Fe species to the subsurface Ce species was well retained. Such an innovative structure of surface iron sulfate and subsurface ceria notably improved the reactivity of NHx species, thus endowing the catalysts with a high NOx reaction efficiency in the presence of SO2. This work unraveled the specific structure effect of surface iron sulfate and subsurface ceria on SO2-toleant NOx reduction and supplied a new point to design SO2-tolerant catalysts by modulating the unique electron transfer between surface sulfate species and subsurface oxides.
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Affiliation(s)
- Xinran Qi
- International Joint Laboratory of Catalytic Chemistry, State Key Laboratory of Advanced Special Steel, Department of Chemistry, Research Center of Nano Science and Technology, College of Sciences, Shanghai University, Shanghai 200444, China
| | - Lupeng Han
- International Joint Laboratory of Catalytic Chemistry, State Key Laboratory of Advanced Special Steel, Department of Chemistry, Research Center of Nano Science and Technology, College of Sciences, Shanghai University, Shanghai 200444, China
| | - Jiang Deng
- International Joint Laboratory of Catalytic Chemistry, State Key Laboratory of Advanced Special Steel, Department of Chemistry, Research Center of Nano Science and Technology, College of Sciences, Shanghai University, Shanghai 200444, China
| | - Tianwei Lan
- International Joint Laboratory of Catalytic Chemistry, State Key Laboratory of Advanced Special Steel, Department of Chemistry, Research Center of Nano Science and Technology, College of Sciences, Shanghai University, Shanghai 200444, China
| | - Fuli Wang
- International Joint Laboratory of Catalytic Chemistry, State Key Laboratory of Advanced Special Steel, Department of Chemistry, Research Center of Nano Science and Technology, College of Sciences, Shanghai University, Shanghai 200444, China
| | - Liyi Shi
- International Joint Laboratory of Catalytic Chemistry, State Key Laboratory of Advanced Special Steel, Department of Chemistry, Research Center of Nano Science and Technology, College of Sciences, Shanghai University, Shanghai 200444, China
| | - Dengsong Zhang
- International Joint Laboratory of Catalytic Chemistry, State Key Laboratory of Advanced Special Steel, Department of Chemistry, Research Center of Nano Science and Technology, College of Sciences, Shanghai University, Shanghai 200444, China
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18
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Molokova A, Borfecchia E, Martini A, Pankin IA, Atzori C, Mathon O, Bordiga S, Wen F, Vennestrøm PNR, Berlier G, Janssens TVW, Lomachenko KA. SO 2 Poisoning of Cu-CHA deNO x Catalyst: The Most Vulnerable Cu Species Identified by X-ray Absorption Spectroscopy. JACS Au 2022; 2:787-792. [PMID: 35557768 PMCID: PMC9088759 DOI: 10.1021/jacsau.2c00053] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/27/2022] [Revised: 04/04/2022] [Accepted: 04/05/2022] [Indexed: 05/11/2023]
Abstract
Cu-exchanged chabazite zeolites (Cu-CHA) are effective catalysts for the NH3-assisted selective catalytic reduction of NO (NH3-SCR) for the abatement of NO x emission from diesel vehicles. However, the presence of a small amount of SO2 in diesel exhaust gases leads to a severe reduction in the low-temperature activity of these catalysts. To shed light on the nature of such deactivation, we characterized a Cu-CHA catalyst under well-defined exposures to SO2 using in situ X-ray absorption spectroscopy. By varying the pretreatment procedure prior to the SO2 exposure, we have selectively prepared CuI and CuII species with different ligations, which are relevant for the NH3-SCR reaction. The highest reactivity toward SO2 was observed for CuII species coordinated to both NH3 and extraframework oxygen, in particular for [CuII 2(NH3)4O2]2+ complexes. Cu species without either ammonia or extraframework oxygen ligands were much less reactive, and the associated SO2 uptake was significantly lower. These results explain why SO2 mostly affects the low-temperature activity of Cu-CHA catalysts, since the dimeric complex [CuII 2(NH3)4O2]2+ is a crucial intermediate in the low-temperature NH3-SCR catalytic cycle.
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Affiliation(s)
- Anastasia
Yu. Molokova
- European
Synchrotron Radiation Facility, 71 avenue des Martyrs, CS 40220, 38043 Grenoble Cedex 9, France
- Department
of Chemistry and NIS Centre, University
of Turin, via Giuria
7,10125 Turin, Italy
| | - Elisa Borfecchia
- Department
of Chemistry and NIS Centre, University
of Turin, via Giuria
7,10125 Turin, Italy
| | - Andrea Martini
- Department
of Chemistry and NIS Centre, University
of Turin, via Giuria
7,10125 Turin, Italy
- The
Smart Materials Research Institute, Southern
Federal University, Sladkova
174/28, 344090 Rostov-on-Don, Russia
| | - Ilia A. Pankin
- The
Smart Materials Research Institute, Southern
Federal University, Sladkova
174/28, 344090 Rostov-on-Don, Russia
| | - Cesare Atzori
- European
Synchrotron Radiation Facility, 71 avenue des Martyrs, CS 40220, 38043 Grenoble Cedex 9, France
| | - Olivier Mathon
- European
Synchrotron Radiation Facility, 71 avenue des Martyrs, CS 40220, 38043 Grenoble Cedex 9, France
| | - Silvia Bordiga
- Department
of Chemistry and NIS Centre, University
of Turin, via Giuria
7,10125 Turin, Italy
| | - Fei Wen
- Umicore
AG & Co, Rodenbacher Chaussee 4, 63457 Hanau, Germany
| | | | - Gloria Berlier
- Department
of Chemistry and NIS Centre, University
of Turin, via Giuria
7,10125 Turin, Italy
| | - Ton V. W. Janssens
- Umicore
Denmark ApS, Kogle Allé
1, 2970 Hørsholm, Denmark
- Email for T.V.W.J.:
| | - Kirill A. Lomachenko
- European
Synchrotron Radiation Facility, 71 avenue des Martyrs, CS 40220, 38043 Grenoble Cedex 9, France
- Email for K.A.L.:
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19
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Shen Z, Liu X, Impeng S, Zhang C, Yan T, Wang P, Zhang D. Alkali and Heavy Metal Copoisoning Resistant Catalytic Reduction of NO x via Liberating Lewis Acid Sites. Environ Sci Technol 2022; 56:5141-5149. [PMID: 35369691 DOI: 10.1021/acs.est.1c08096] [Citation(s) in RCA: 10] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/14/2023]
Abstract
The catalyst deactivation caused by the coexistence of alkali and heavy metals remains an obstacle for selective catalytic reduction of NOx with NH3. Moreover, the copoisoning mechanism of alkali and heavy metals is still unclear. Herein, the copoisoning mechanism of K and Cd was revealed from the adsorption and variation of reaction intermediates at a molecular level through time-resolved in situ spectroscopy combined with theoretical calculations. The alkali metal K mainly decreased the adsorption of NH3 on Lewis acid sites and altered the reaction more depending on the formation of the NH4NO3 intermediate, which is highly related to NOx adsorption and activation. However, Cd further inhibited the generation of active nitrate intermediates and thus decreased the NOx abatement about 60% on potassium-poisoned CeTiOx catalysts. Physically mixing with acid additives for CeTiOx catalysts could significantly liberate the active Lewis acid sites from the occupation of alkali metals and relieve the high dependence on NOx adsorption and activation, thus recovering the NOx removal rate to the initial state. This work revealed the copoisoning mechanism of K and Cd on Ce-based de-NOx catalysts and developed a facile anti-poisoning strategy, which paves a way for the development of durable catalysts among alkali and heavy metal copoisoning resistant catalytic reduction of NOx.
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Affiliation(s)
- Zhi Shen
- State Key Laboratory of Advanced Special Steel, School of Materials Science and Engineering, International Joint Laboratory of Catalytic Chemistry, College of Sciences, Shanghai University, Shanghai 200444, China
| | - Xiangyu Liu
- State Key Laboratory of Advanced Special Steel, School of Materials Science and Engineering, International Joint Laboratory of Catalytic Chemistry, College of Sciences, Shanghai University, Shanghai 200444, China
| | - Sarawoot Impeng
- National Nanotechnology Center, National Science and Technology Development Agency, Klong Luang, Pathum Thani 12120, Thailand
| | - Chengbiao Zhang
- State Key Laboratory of Advanced Special Steel, School of Materials Science and Engineering, International Joint Laboratory of Catalytic Chemistry, College of Sciences, Shanghai University, Shanghai 200444, China
| | - Tingting Yan
- State Key Laboratory of Advanced Special Steel, School of Materials Science and Engineering, International Joint Laboratory of Catalytic Chemistry, College of Sciences, Shanghai University, Shanghai 200444, China
| | - Penglu Wang
- State Key Laboratory of Advanced Special Steel, School of Materials Science and Engineering, International Joint Laboratory of Catalytic Chemistry, College of Sciences, Shanghai University, Shanghai 200444, China
| | - Dengsong Zhang
- State Key Laboratory of Advanced Special Steel, School of Materials Science and Engineering, International Joint Laboratory of Catalytic Chemistry, College of Sciences, Shanghai University, Shanghai 200444, China
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20
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Hu W, He J, Liu X, Yu H, Jia X, Yan T, Han L, Zhang D. SO 2- and H 2O-Tolerant Catalytic Reduction of NO x at a Low Temperature via Engineering Polymeric VO x Species by CeO 2. Environ Sci Technol 2022; 56:5170-5178. [PMID: 35369692 DOI: 10.1021/acs.est.1c08715] [Citation(s) in RCA: 10] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/14/2023]
Abstract
Selective catalytic reduction (SCR) of NOx over V2O5-based oxide catalysts has been widely used, but it is still a challenge to efficiently reduce NOx at low temperatures under SO2 and H2O co-existence. Herein, SO2- and H2O-tolerant catalytic reduction of NOx at a low temperature has been originally demonstrated via engineering polymeric VOx species by CeO2. The polymeric VOx species were tactfully engineered on Ce-V2O5 composite active sites via the surface occupation effect of Ce, and the obtained catalysts exhibited remarkable low-temperature activity and strong SO2 and H2O tolerance at 250 °C. The strong interaction between Ce and V species induced the electron transfer from V to Ce and tuned the SCR reaction via the E-R pathway between the NH4+/NH3 species and gaseous NO. In the presence of SO2 and H2O, the polymeric VOx species had not been hardly influenced, while the formation of sulfate species on Ce sites not only promoted the adsorption of NH4+ species and the reaction between gaseous NO and NH4+ but also facilitated the decomposition of ammonium bisulfate through weakening the strong bond between HSO4- and NH4+. This work provided a new strategy for SO2- and H2O-tolerant catalytic reduction of NOx at a low temperature.
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Affiliation(s)
- Weiwei Hu
- International Joint Laboratory of Catalytic Chemistry, State Key Laboratory of Advanced Special Steel, Department of Chemistry, Research Center of Nano Science and Technology, College of Sciences, Shanghai University, 200444 Shanghai, China
| | - Jiebing He
- International Joint Laboratory of Catalytic Chemistry, State Key Laboratory of Advanced Special Steel, Department of Chemistry, Research Center of Nano Science and Technology, College of Sciences, Shanghai University, 200444 Shanghai, China
| | - Xiangyu Liu
- International Joint Laboratory of Catalytic Chemistry, State Key Laboratory of Advanced Special Steel, Department of Chemistry, Research Center of Nano Science and Technology, College of Sciences, Shanghai University, 200444 Shanghai, China
| | - Huijun Yu
- International Joint Laboratory of Catalytic Chemistry, State Key Laboratory of Advanced Special Steel, Department of Chemistry, Research Center of Nano Science and Technology, College of Sciences, Shanghai University, 200444 Shanghai, China
| | - Xinyu Jia
- International Joint Laboratory of Catalytic Chemistry, State Key Laboratory of Advanced Special Steel, Department of Chemistry, Research Center of Nano Science and Technology, College of Sciences, Shanghai University, 200444 Shanghai, China
| | - Tingting Yan
- International Joint Laboratory of Catalytic Chemistry, State Key Laboratory of Advanced Special Steel, Department of Chemistry, Research Center of Nano Science and Technology, College of Sciences, Shanghai University, 200444 Shanghai, China
| | - Lupeng Han
- International Joint Laboratory of Catalytic Chemistry, State Key Laboratory of Advanced Special Steel, Department of Chemistry, Research Center of Nano Science and Technology, College of Sciences, Shanghai University, 200444 Shanghai, China
| | - Dengsong Zhang
- International Joint Laboratory of Catalytic Chemistry, State Key Laboratory of Advanced Special Steel, Department of Chemistry, Research Center of Nano Science and Technology, College of Sciences, Shanghai University, 200444 Shanghai, China
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Zhao Y, Shi L, Shen Y, Zhou J, Jia Z, Yan T, Wang P, Zhang D. Self-Defense Effects of Ti-Modified Attapulgite for Alkali-Resistant NO x Catalytic Reduction. Environ Sci Technol 2022; 56:4386-4395. [PMID: 35262342 DOI: 10.1021/acs.est.1c07996] [Citation(s) in RCA: 11] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/14/2023]
Abstract
Nowadays, the serious deactivation of deNOx catalysts caused by alkali metal poisoning was still a huge bottleneck in the practical application of selective catalytic reduction of NOx with NH3. Herein, alkali-resistant NOx catalytic reduction over metal oxide catalysts using Ti-modified attapulgite (ATP) as supports has been originally demonstrated. The self-defense effects of Ti-modified ATP for alkali-resistant NOx catalytic reduction have been clarified. Ti-modified ATP with self-defense ability was obtained by removing alkaline metal cation impurities in the natural ATP materials without destroying its initial layered-chain structure through the ion-exchange procedure, accompanied with an obvious enrichment of Brønsted acid and Lewis acid sites. The self-defense effects embodied that both ion-exchanged Ti octahedral centers and abundant Si-OH sites in the Ti-ion-exchange-modified ATP could effectively anchor alkali metals via coordinate bonding or ion-exchange process, which induced alkali metals to be immobilized by the Ti-ion-exchange-modified ATP carrier rather than impair active species. Under this special protection of self-defense effects, Ti-ion-exchange-modified ATP supported catalysts still retained plentiful acidic sites and superior redox ability even after alkali metal poisoning, giving rise to the maintenance of sufficient NHx and NOx adsorption and the subsequent efficient reaction, which in turn resulted in high NOx catalytic reduction capacity of the catalyst. The strategy provided new inspiration for the development of novel and efficient selective catalytic reduction of NOx with NH3 (NH3-SCR) catalysts with high alkali resistance.
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Affiliation(s)
- Yufei Zhao
- International Joint Laboratory of Catalytic Chemistry, College of Sciences, Shanghai University, Shanghai 200444, China
| | - Liyi Shi
- International Joint Laboratory of Catalytic Chemistry, College of Sciences, Shanghai University, Shanghai 200444, China
| | - Yongjie Shen
- International Joint Laboratory of Catalytic Chemistry, College of Sciences, Shanghai University, Shanghai 200444, China
| | - Jialun Zhou
- International Joint Laboratory of Catalytic Chemistry, College of Sciences, Shanghai University, Shanghai 200444, China
| | - Zhaozhao Jia
- International Joint Laboratory of Catalytic Chemistry, College of Sciences, Shanghai University, Shanghai 200444, China
| | - Tingting Yan
- International Joint Laboratory of Catalytic Chemistry, College of Sciences, Shanghai University, Shanghai 200444, China
| | - Penglu Wang
- International Joint Laboratory of Catalytic Chemistry, College of Sciences, Shanghai University, Shanghai 200444, China
| | - Dengsong Zhang
- International Joint Laboratory of Catalytic Chemistry, College of Sciences, Shanghai University, Shanghai 200444, China
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Xu G, Li H, Yu Y, He H. Dynamic Change of Active Sites of Supported Vanadia Catalysts for Selective Catalytic Reduction of Nitrogen Oxides. Environ Sci Technol 2022; 56:3710-3718. [PMID: 35195409 DOI: 10.1021/acs.est.1c07739] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/14/2023]
Abstract
Selective catalytic reduction of NOx by ammonia (NH3-SCR) on V2O5/TiO2 catalysts is a widely used commercial technology in power plants and diesel vehicles due to its high elimination efficiency for NOx removal. However, the mechanistic aspects of the NH3-SCR reaction, especially the active sites on the V2O5/TiO2 catalysts, are still a puzzle. Herein, using combined operando spectroscopy and density functional theory calculations, we found that the reactivity of the Lewis acid site was significantly overestimated due to its conversion to the Brønsted acid site. Such interconversion makes it challenging to measure the intrinsic reactivity of different acid sites accurately. In contrast, the abundant V-OH Brønsted acid sites govern the overall NOx reduction rate in realistic exhaust containing water vapor. Moreover, the vanadia species cycle between V5+═O and V4+-OH during NOx reduction, and the re-oxidation of V4+ species to form V5+ is the rate-determining step.
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Affiliation(s)
- Guangyan Xu
- State Key Joint Laboratory of Environment Simulation and Pollution Control, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing 100085, China
| | - Hao Li
- State Key Joint Laboratory of Environment Simulation and Pollution Control, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing 100085, China
| | - Yunbo Yu
- State Key Joint Laboratory of Environment Simulation and Pollution Control, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing 100085, China
- Center for Excellence in Regional Atmospheric Environment, Institute of Urban Environment, Chinese Academy of Sciences, Xiamen 361021, China
- University of Chinese Academy of Sciences, Beijing 100049, China
| | - Hong He
- State Key Joint Laboratory of Environment Simulation and Pollution Control, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing 100085, China
- Center for Excellence in Regional Atmospheric Environment, Institute of Urban Environment, Chinese Academy of Sciences, Xiamen 361021, China
- University of Chinese Academy of Sciences, Beijing 100049, China
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23
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Zhang Y, Zhu H, Zhang T, Li J, Chen J, Peng Y, Li J. Revealing the Synergistic Deactivation Mechanism of Hydrothermal Aging and SO 2 Poisoning on Cu/SSZ-13 under SCR Condition. Environ Sci Technol 2022; 56:1917-1926. [PMID: 34856804 DOI: 10.1021/acs.est.1c06068] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/13/2023]
Abstract
In real-world application, Cu/SSZ-13 simultaneously suffers severe deactivation from hydrothermal aging and SO2 poisoning during the periodic regeneration of diesel particulate filter (DPF). Herein, we first investigated the synergistic deactivation mechanism of hydrothermal aging and SO2 poisoning on Cu/SSZ-13 under SCR condition. Hydrothermal aging alone induces more severe degradation of selective catalytic reduction (SCR) performance than SO2 poisoning alone, while the presence of SO2 during hydrothermal aging causes further worse SCR performance compared with hydrothermal aging alone. Hydrothermal aging not only damages Si-OH-Al sites, particularly in four-membered ring (4MR) of the CHA cage, but also brings the conversion of ZCuOH, leading to the formation of inactive CuO/CuAlOx species. By contrast, SO2 poisoning alone is more prone to promote the transformation of ZCuOH to Z2Cu. Synergistic deactivation of hydrothermal aging and SO2 poisoning would exacerbate the damage of Si-OH-Al sites and then the formation of CuO/CuAlOx species. These results are expected to assist the knowledge-based catalyst design for diesel aftertreatment applications.
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Affiliation(s)
- Yani Zhang
- State Key Joint Laboratory of Environment Simulation and Pollution Control, School of Environment, Tsinghua University, Beijing 100084, China
| | - Hongchang Zhu
- School of Environment and Natural Resources, Renmin University of China, Beijing 100872, China
| | - Tao Zhang
- School of Environment and Natural Resources, Renmin University of China, Beijing 100872, China
| | - Jie Li
- School of Environment and Natural Resources, Renmin University of China, Beijing 100872, China
| | - Jianjun Chen
- State Key Joint Laboratory of Environment Simulation and Pollution Control, School of Environment, Tsinghua University, Beijing 100084, China
| | - Yue Peng
- State Key Joint Laboratory of Environment Simulation and Pollution Control, School of Environment, Tsinghua University, Beijing 100084, China
| | - Junhua Li
- State Key Joint Laboratory of Environment Simulation and Pollution Control, School of Environment, Tsinghua University, Beijing 100084, China
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Abstract
Selective catalytic reduction of nitrogen oxides with ammonia (NH3-SCR) is an efficient NOx abatement strategy, but deNOx catalysts suffer from serious deactivation due to the coexistence of multiple poisoning substances such as K, SO2, etc. in the flue gas. It is essential to understand the interaction among various poisons and their effects on NOx abatement. Here, we unexpectedly identified the K migration behavior induced by SO2 over K-poisoned FeVO4/TiO2 catalysts, which led to alkali-poisoning buffering and activity recovery. It has been demonstrated that the K would occupy both redox and acidic sites, which severely reduced the reactivity of FeVO4/TiO2 catalysts. After the sulfuration of the K-poisoned catalyst, SO2 preferred to be combined with the surface K2O, lengthened the K-OFe and K-OV, and thus released the active sites poisoned by K2O, thereby preserving an increase in the activity. As a result, for the K-poisoned catalyst, the conversion of NOx increased from 21 to 97% at 270 °C after the sulfuration process. This work contributes to the understanding of the specific interaction between alkali metals and SO2 on deNOx catalysts and provides a novel strategy for the adaptive use of one poisoning substance to counter another for practical NOx reduction.
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Affiliation(s)
- Zhiping Si
- International Joint Laboratory of Catalytic Chemistry, State Key Laboratory of Advanced Special Steel, Department of Chemistry, Research Center of Nano Science and Technology, College of Sciences, Shanghai University, Shanghai 200444, China
| | - Yongjie Shen
- International Joint Laboratory of Catalytic Chemistry, State Key Laboratory of Advanced Special Steel, Department of Chemistry, Research Center of Nano Science and Technology, College of Sciences, Shanghai University, Shanghai 200444, China
| | - Jiebing He
- International Joint Laboratory of Catalytic Chemistry, State Key Laboratory of Advanced Special Steel, Department of Chemistry, Research Center of Nano Science and Technology, College of Sciences, Shanghai University, Shanghai 200444, China
| | - Tingting Yan
- International Joint Laboratory of Catalytic Chemistry, State Key Laboratory of Advanced Special Steel, Department of Chemistry, Research Center of Nano Science and Technology, College of Sciences, Shanghai University, Shanghai 200444, China
| | - Jianping Zhang
- International Joint Laboratory of Catalytic Chemistry, State Key Laboratory of Advanced Special Steel, Department of Chemistry, Research Center of Nano Science and Technology, College of Sciences, Shanghai University, Shanghai 200444, China
| | - Jiang Deng
- International Joint Laboratory of Catalytic Chemistry, State Key Laboratory of Advanced Special Steel, Department of Chemistry, Research Center of Nano Science and Technology, College of Sciences, Shanghai University, Shanghai 200444, China
| | - Dengsong Zhang
- International Joint Laboratory of Catalytic Chemistry, State Key Laboratory of Advanced Special Steel, Department of Chemistry, Research Center of Nano Science and Technology, College of Sciences, Shanghai University, Shanghai 200444, China
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Mozgawa B, Zasada F, Fedyna M, Góra-Marek K, Tabor E, Mlekodaj K, Dědeček J, Zhao Z, Pietrzyk P, Sojka Z. Analysis of NH 3 -TPD Profiles for CuSSZ-13 SCR Catalyst of Controlled Al Distribution - Complexity Resolved by First Principles Thermodynamics of NH 3 Desorption, IR and EPR Insight into Cu Speciation*. Chemistry 2021; 27:17159-17180. [PMID: 34751471 DOI: 10.1002/chem.202102790] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/05/2021] [Indexed: 11/06/2022]
Abstract
NH3 temperature-programmed desorption (NH3 -TPD) is frequently used for probing the nature of the active sites in CuSSZ-13 zeolite for selective catalytic reduction (SCR) of NOx . Herein, we propose an interpretation of NH3 -TPD results, which takes into account the temperature-induced dynamics of NH3 interaction with the active centers. It is based on a comprehensive DFT/GGA+D and first-principles thermodynamic (FPT) modeling of NH3 adsorption on single Cu2+ , Cu+ , [CuOH]+ centers, dimeric [Cu-O-Cu]2+ , [Cu-O2 2- -Cu]2 species, segregated CuO nanocrystals and Brønsted acid sites (BAS). Theoretical TPD profiles are compared with the experimental data measured for samples of various Si/Al ratios and distribution of Al within the zeolite framework. Copper reduction, its relocation, followed by the intrazeolite olation/oxolation processes, which are concomitant with NH3 desorption, were revealed by electron paramagnetic resonance (EPR) and IR. DFT/FPT results show that the peaks in the desorption profiles cannot be assigned univocally to the particular Cu and BAS centers, since the observed low-, medium- and high-temperature desorption bands have contributions coming from several species, which dynamically change their speciation and redox states during NH3 -TPD experiment. Thus, a rigorous interpretation of the NH3 -TPD profiles of CuSSZ-13 in terms of the strength and concentration of the active centers of a particular type is problematic. Nonetheless, useful connections for molecular interpretation of TPD profiles can be established between the individual component peaks and the corresponding ensembles of the adsorption centers.
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Affiliation(s)
- Bartosz Mozgawa
- Faculty of Chemistry, Jagiellonian University, ul. Gronostajowa 2, 30-387, Krakow, Poland
| | - Filip Zasada
- Faculty of Chemistry, Jagiellonian University, ul. Gronostajowa 2, 30-387, Krakow, Poland
| | - Monika Fedyna
- Faculty of Chemistry, Jagiellonian University, ul. Gronostajowa 2, 30-387, Krakow, Poland
| | - Kinga Góra-Marek
- Faculty of Chemistry, Jagiellonian University, ul. Gronostajowa 2, 30-387, Krakow, Poland
| | - Edyta Tabor
- J. Heyrovský Institute of Physical Chemistry, Czech Academic Sciences, Dolejškova 3, Prague, 18223, Czech Republic
| | - Kinga Mlekodaj
- J. Heyrovský Institute of Physical Chemistry, Czech Academic Sciences, Dolejškova 3, Prague, 18223, Czech Republic
| | - Jiří Dědeček
- J. Heyrovský Institute of Physical Chemistry, Czech Academic Sciences, Dolejškova 3, Prague, 18223, Czech Republic
| | - Zhen Zhao
- Institute of Catalysis for Energy and Environment, College of Chemistry and Chemical Engineering, Shenyang Normal University, Shenyang, Liaoning, 110034, P. R. China
| | - Piotr Pietrzyk
- Faculty of Chemistry, Jagiellonian University, ul. Gronostajowa 2, 30-387, Krakow, Poland
| | - Zbigniew Sojka
- Faculty of Chemistry, Jagiellonian University, ul. Gronostajowa 2, 30-387, Krakow, Poland
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Zhu N, Qian F, Xu X, Wang M, Teng Q. Thermogravimetric Experiment of Urea at Constant Temperatures. Materials (Basel) 2021; 14:ma14206190. [PMID: 34683779 PMCID: PMC8539392 DOI: 10.3390/ma14206190] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 09/15/2021] [Revised: 10/11/2021] [Accepted: 10/14/2021] [Indexed: 11/23/2022]
Abstract
There are still many unsolved mysteries in the thermal decomposition process of urea. This paper studied the thermal decomposition process of urea at constant temperatures by the thermal gravimetric–mass spectrometry analysis method. The results show that there are three obvious stages of mass loss during the thermal decomposition process of urea, which is closely related to the temperature. When the temperature was below 160 °C, urea decomposition almost did not occur, and molten urea evaporated slowly. When the temperature was between 180 and 200 °C, the content of biuret, one of the by-products in the thermal decomposition of urea, reached a maximum. When the temperature was higher than 200 °C, the first stage of mass loss was completed quickly, and urea and biuret rapidly broke down. When the temperature was about 240 °C, there were rarely urea and biuret in residual substance; however, the content of cyanuric acid was still rising. When the temperature was higher than 280°C, there was a second stage of mass loss. In the second stage of mass loss, when the temperature was higher than 330 °C, mass decreased rapidly, which was mainly due to the decomposition of cyanuric acid. When the temperature was higher than 380 °C, the third stage of mass loss occurred. However, when the temperature was higher than 400 °C, and after continuous heating was applied for a sufficiently long time, the residual mass was reduced to almost zero eventually.
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Affiliation(s)
- Neng Zhu
- School of Automotive and Transportation Engineering, Wuhan University of Science and Technology, Wuhan 430081, China; (N.Z.); (X.X.)
| | - Feng Qian
- School of Automotive and Transportation Engineering, Wuhan University of Science and Technology, Wuhan 430081, China; (N.Z.); (X.X.)
- Correspondence: ; Tel.: +86-180-6206-0988
| | - Xiaowei Xu
- School of Automotive and Transportation Engineering, Wuhan University of Science and Technology, Wuhan 430081, China; (N.Z.); (X.X.)
| | - Mingda Wang
- Chinese Academy of Environmental Sciences, Beijing 100012, China; (M.W.); (Q.T.)
| | - Qi Teng
- Chinese Academy of Environmental Sciences, Beijing 100012, China; (M.W.); (Q.T.)
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27
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Lee MS, Kim SI, Jeong B, Park JW, Kim T, Lee JW, Kwon G, Lee DH. Ammonium Ion Enhanced V 2O 5-WO 3/TiO 2 Catalysts for Selective Catalytic Reduction with Ammonia. Nanomaterials (Basel) 2021; 11:nano11102677. [PMID: 34685118 PMCID: PMC8540173 DOI: 10.3390/nano11102677] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 08/31/2021] [Revised: 09/28/2021] [Accepted: 10/05/2021] [Indexed: 11/18/2022]
Abstract
Selective catalytic reduction (SCR) is the most efficient NOX removal technology, and the vanadium-based catalyst is mainly used in SCR technology. The vanadium-based catalyst showed higher NOX removal performance in the high-temperature range but catalytic efficiency decreased at lower temperatures, following exposure to SOX because of the generation of ammonium sulfate on the catalyst surface. To overcome these limitations, we coated an NH4+ layer on a vanadium-based catalyst. After silane coating the V2O5-WO3/TiO2 catalyst by vapor evaporation, the silanized catalyst was heat treated under NH3 gas. By decomposing the silane on the surface, an NH4+ layer was formed on the catalyst surface through a substitution reaction. We observed high NOX removal efficiency over a wide temperature range by coating an NH4+ layer on a vanadium-based catalyst. This layer shows high proton conductivity, which leads to the reduction of vanadium oxides and tungsten oxide; additionally, the NOX removal performance was improved over a wide temperature range. These findings provide a new mothed to develop SCR catalyst with high efficiency at a wide temperature range.
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Affiliation(s)
- Min Seong Lee
- Green Materials & Processes R&D Group, Korea Institute of Industrial Technology, Ulsan 44413, Korea; (M.S.L.); (S.-I.K.); (B.J.); (T.K.)
- Department of Materials Science & Engineering, Pusan National University, Busan 46241, Korea; (J.-W.P.); (J.W.L.)
| | - Sun-I Kim
- Green Materials & Processes R&D Group, Korea Institute of Industrial Technology, Ulsan 44413, Korea; (M.S.L.); (S.-I.K.); (B.J.); (T.K.)
| | - Bora Jeong
- Green Materials & Processes R&D Group, Korea Institute of Industrial Technology, Ulsan 44413, Korea; (M.S.L.); (S.-I.K.); (B.J.); (T.K.)
| | - Jin-Woo Park
- Department of Materials Science & Engineering, Pusan National University, Busan 46241, Korea; (J.-W.P.); (J.W.L.)
- NANO. Co., Ltd., Sangju 37257, Korea
| | - Taehyo Kim
- Green Materials & Processes R&D Group, Korea Institute of Industrial Technology, Ulsan 44413, Korea; (M.S.L.); (S.-I.K.); (B.J.); (T.K.)
| | - Jung Woo Lee
- Department of Materials Science & Engineering, Pusan National University, Busan 46241, Korea; (J.-W.P.); (J.W.L.)
| | - Gibum Kwon
- Department of Mechanical Engineering, University of Kansas, Lawrence, KS 66045, USA
- Correspondence: (G.K.); (D.H.L.); Tel.: +1-785-864-1086 (G.K.); +82-52-980-6709 (D.H.L.); Fax: +82-52-980-6669 (D.H.L.)
| | - Duck Hyun Lee
- Green Materials & Processes R&D Group, Korea Institute of Industrial Technology, Ulsan 44413, Korea; (M.S.L.); (S.-I.K.); (B.J.); (T.K.)
- Correspondence: (G.K.); (D.H.L.); Tel.: +1-785-864-1086 (G.K.); +82-52-980-6709 (D.H.L.); Fax: +82-52-980-6669 (D.H.L.)
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28
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Feng C, Wang P, Liu X, Wang F, Yan T, Zhang J, Zhou G, Zhang D. Alkali-Resistant Catalytic Reduction of NO x via Naturally Coupling Active and Poisoning Sites. Environ Sci Technol 2021; 55:11255-11264. [PMID: 34323076 DOI: 10.1021/acs.est.1c02061] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/13/2023]
Abstract
Releasing the poisoning effect of alkali metals over catalysts is still an intractable issue for selective catalytic reduction (SCR) of NOx with ammonia. The presence of K in fly ash always dramatically suppressed catalytic activity by impairing acidity and redox properties, leading to severe reduction of lifetime for SCR catalysts. Herein, alkali-resistant NOx reduction over TiO2-supported Fe2(SO4)3 catalysts was originally demonstrated via naturally coupling active and poisoning sites. Notably, TiO2-supported Fe2(SO4)3 catalysts expressed admirable NOx conversion and K resistance within a quite broad temperature window of 200-500 °C. The catalysts with more conserved sulfate species revealed that sulfate groups preferred to migrate from the bulk phase to surface, thus effectively binding with K poisons to release the damage on iron active sites. Because of protection effects of migrated sulfates and closely coupling effects with Fe active sites, NH3 and NO adsorption amounts and rates were well maintained. In this way, Fe metal sites and sulfate species closely coupled together on a self-preserved TiO2-supported Fe2(SO4)3 catalyst played essential roles as highly active sites and unique poisoning sites. This work paves a new way to design SCR catalysts with superior alkali resistance that are more reliable in practical deNOx application.
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Affiliation(s)
- Chong Feng
- State Key Laboratory of Advanced Special Steel, School of Materials Science and Engineering, International Joint Laboratory of Catalytic Chemistry, College of Sciences, Shanghai University, Shanghai 200444, China
| | - Penglu Wang
- State Key Laboratory of Advanced Special Steel, School of Materials Science and Engineering, International Joint Laboratory of Catalytic Chemistry, College of Sciences, Shanghai University, Shanghai 200444, China
| | - Xiangyu Liu
- State Key Laboratory of Advanced Special Steel, School of Materials Science and Engineering, International Joint Laboratory of Catalytic Chemistry, College of Sciences, Shanghai University, Shanghai 200444, China
| | - Fuli Wang
- State Key Laboratory of Advanced Special Steel, School of Materials Science and Engineering, International Joint Laboratory of Catalytic Chemistry, College of Sciences, Shanghai University, Shanghai 200444, China
| | - Tingting Yan
- State Key Laboratory of Advanced Special Steel, School of Materials Science and Engineering, International Joint Laboratory of Catalytic Chemistry, College of Sciences, Shanghai University, Shanghai 200444, China
| | - Jianping Zhang
- State Key Laboratory of Advanced Special Steel, School of Materials Science and Engineering, International Joint Laboratory of Catalytic Chemistry, College of Sciences, Shanghai University, Shanghai 200444, China
| | - Guangyuan Zhou
- Dalian Institute of Chemical Physics, Chinese Academy of Sciences, Dalian 116023, China
| | - Dengsong Zhang
- State Key Laboratory of Advanced Special Steel, School of Materials Science and Engineering, International Joint Laboratory of Catalytic Chemistry, College of Sciences, Shanghai University, Shanghai 200444, China
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29
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Li Y, Cai S, Wang P, Yan T, Zhang J, Zhang D. Improved NO x Reduction over Phosphate-Modified Fe 2O 3/TiO 2 Catalysts Via Tailoring Reaction Paths by In Situ Creating Alkali-Poisoning Sites. Environ Sci Technol 2021; 55:9276-9284. [PMID: 34142799 DOI: 10.1021/acs.est.1c01722] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/12/2023]
Abstract
The deactivation issue arising from alkali poisoning over catalysts is still a challenge for the selective catalytic reduction of NOx by NH3. Herein, improved NOx reduction in the presence of alkaline metals over phosphate-modified Fe2O3/TiO2 catalysts has been originally demonstrated via tailoring the reaction paths by in situ creating alkali-poisoning sites. The introduction of phosphate results in the partial formation of iron phosphate species and makes the catalyst to mainly exhibit the characteristics of FePO4, which is responsible for the widened temperature window and enhanced alkali resistance. The tetrahedral [FeO4]/[PO4] structures in iron phosphate act as the Brønsted acid sites to increase the catalyst surface acidity. In addition, the formation of an Fe-O-P structure enhances the redox ability and increases surface adsorbed oxygen. Furthermore, the created phosphate groups (PO43-) serving as alkali-poisoning sites preferentially combine with potassium so that iron species on the active sites are protected. Therefore, the enhanced NH3 species adsorption capacity, improved redox ability, and active nitrate species remaining in the phosphate-modified Fe2O3/TiO2 catalyst ensure the de-NOx activity after being poisoned by alkali metals through the Langmuir-Hinshelwood reaction pathway. Hopefully, this novel strategy could provide an inspiration to design novel catalysts to control NOx emission with extraordinary resistance to alkaline metals.
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Affiliation(s)
- Yue Li
- International Joint Laboratory of Catalytic Chemistry, State Key Laboratory of Advanced Special Steel, Department of Chemistry, Research Center of Nano Science and Technology, College of Sciences, Shanghai University, Shanghai 200444, China
- Special Glass Key Lab of Hainan Province, School of Materials Science and Engineering, Hainan University, Haikou, Hainan 570228, China
| | - Sixiang Cai
- Special Glass Key Lab of Hainan Province, School of Materials Science and Engineering, Hainan University, Haikou, Hainan 570228, China
| | - Penglu Wang
- International Joint Laboratory of Catalytic Chemistry, State Key Laboratory of Advanced Special Steel, Department of Chemistry, Research Center of Nano Science and Technology, College of Sciences, Shanghai University, Shanghai 200444, China
| | - Tingting Yan
- International Joint Laboratory of Catalytic Chemistry, State Key Laboratory of Advanced Special Steel, Department of Chemistry, Research Center of Nano Science and Technology, College of Sciences, Shanghai University, Shanghai 200444, China
| | - Jianping Zhang
- International Joint Laboratory of Catalytic Chemistry, State Key Laboratory of Advanced Special Steel, Department of Chemistry, Research Center of Nano Science and Technology, College of Sciences, Shanghai University, Shanghai 200444, China
| | - Dengsong Zhang
- International Joint Laboratory of Catalytic Chemistry, State Key Laboratory of Advanced Special Steel, Department of Chemistry, Research Center of Nano Science and Technology, College of Sciences, Shanghai University, Shanghai 200444, China
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30
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Lee MS, Kim SI, Lee MJ, Ye B, Kim T, Kim HD, Lee JW, Lee DH. Effect of Catalyst Crystallinity on V-Based Selective Catalytic Reduction with Ammonia. Nanomaterials (Basel) 2021; 11:1452. [PMID: 34070897 DOI: 10.3390/nano11061452] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 05/04/2021] [Revised: 05/23/2021] [Accepted: 05/24/2021] [Indexed: 12/04/2022]
Abstract
In this study, we synthesized V2O5-WO3/TiO2 catalysts with different crystallinities via one-sided and isotropic heating methods. We then investigated the effects of the catalysts’ crystallinity on their acidity, surface species, and catalytic performance through various analysis techniques and a fixed-bed reactor experiment. The isotropic heating method produced crystalline V2O5 and WO3, increasing the availability of both Brønsted and Lewis acid sites, while the one-sided method produced amorphous V2O5 and WO3. The crystalline structure of the two species significantly enhanced NO2 formation, causing more rapid selective catalytic reduction (SCR) reactions and greater catalyst reducibility for NOX decomposition. This improved NOX removal efficiency and N2 selectivity for a wider temperature range of 200 °C–450 °C. Additionally, the synthesized, crystalline catalysts exhibited good resistance to SO2, which is common in industrial flue gases. Through the results reported herein, this study may contribute to future studies on SCR catalysts and other catalyst systems.
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Florea OG, Stănoiu A, Gheorghe M, Cobianu C, Neaţu F, Trandafir MM, Neaţu Ş, Florea M, Simion CE. Methane Combustion Using Pd Deposited on CeO x-MnO x/La-Al 2O 3 Pellistors. Materials (Basel) 2020; 13:ma13214888. [PMID: 33143340 PMCID: PMC7663723 DOI: 10.3390/ma13214888] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 10/09/2020] [Revised: 10/26/2020] [Accepted: 10/27/2020] [Indexed: 06/11/2023]
Abstract
Pd deposited on CeOx-MnOx/La-Al2O3 has been prepared as a sensitive material for methane (CH4) detection. The effect of different amounts (1.25%, 2.5% and 5%) of Pd loading has been investigated. The as prepared materials were deposited on Pt microcoils using a drop-coating method, as a way of developing pellistors operated using a Wheatstone bridge configuration. By spanning the operating temperature range between 300 °C and 550 °C, we established the linearity region as well as the maximum sensitivity towards 4900 ppm of CH4. By making use of the sigmoid dependence of the output voltage signal from the Wheatstone bridge, the gas surface reaction and diffusion phenomena have been decoupled. The pellistor with 5% Pd deposited on CeOx-MnOx/La-Al2O3 exhibited the highest selective-sensitivity in the benefit of CH4 detection against threshold limits of carbon monoxide (CO), sulfur dioxide (SO2) and hydrogen sulfide (H2S). Accordingly, adjusting the percent of Pd makes the preparation strategies of pellistors good candidates towards CH4 detection.
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Affiliation(s)
- Ovidiu G. Florea
- Laboratory of Atomic Structures and Defects in Advanced Materials, National Institute of Materials Physics, Atomistilor 405A, 077125 Magurele, Romania; (O.G.F.); (A.S.)
| | - Adelina Stănoiu
- Laboratory of Atomic Structures and Defects in Advanced Materials, National Institute of Materials Physics, Atomistilor 405A, 077125 Magurele, Romania; (O.G.F.); (A.S.)
| | - Marin Gheorghe
- NANOM-MEMS SRL, G. Cosbuc 9, 505400 Rasnov, Romania; (M.G.); (C.C.)
| | - Cornel Cobianu
- NANOM-MEMS SRL, G. Cosbuc 9, 505400 Rasnov, Romania; (M.G.); (C.C.)
| | - Florentina Neaţu
- Laboratory of Nanoscale Condensed Matter, National Institute of Materials Physics, Atomistilor 405A, 077125 Magurele, Romania; (F.N.); (M.M.T.); (Ş.N.)
| | - Mihaela M. Trandafir
- Laboratory of Nanoscale Condensed Matter, National Institute of Materials Physics, Atomistilor 405A, 077125 Magurele, Romania; (F.N.); (M.M.T.); (Ş.N.)
| | - Ştefan Neaţu
- Laboratory of Nanoscale Condensed Matter, National Institute of Materials Physics, Atomistilor 405A, 077125 Magurele, Romania; (F.N.); (M.M.T.); (Ş.N.)
| | - Mihaela Florea
- Laboratory of Multifunctional Materials and Structures, National Institute of Materials Physics, Atomistilor 405A, 077125 Magurele, Romania;
| | - Cristian E. Simion
- Laboratory of Atomic Structures and Defects in Advanced Materials, National Institute of Materials Physics, Atomistilor 405A, 077125 Magurele, Romania; (O.G.F.); (A.S.)
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32
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Zengel D, Koch P, Torkashvand B, Grunwaldt J, Casapu M, Deutschmann O. Emission of Toxic HCN During NO x Removal by Ammonia SCR in the Exhaust of Lean-Burn Natural Gas Engines. Angew Chem Int Ed Engl 2020; 59:14423-14428. [PMID: 32391644 PMCID: PMC7497226 DOI: 10.1002/anie.202003670] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/11/2020] [Revised: 04/28/2020] [Indexed: 11/06/2022]
Abstract
Reducing greenhouse gas and pollutant emissions is one of the most stringent priorities of our society to minimize their dramatic effects on health and environment. Natural gas (NG) engines, in particular at lean conditions, emit less CO2 in comparison to combustion engines operated with liquid fuels but NG engines still require emission control devices for NOx removal. Using state-of-the-art technologies for selective catalytic reduction (SCR) of NOx with NH3 , we evaluated the interplay of the reducing agent NH3 and formaldehyde, which is always present in the exhaust of NG engines. Our results show that a significant amount of highly toxic hydrogen cyanide (HCN) is formed. All catalysts tested partially convert formaldehyde to HCOOH and CO. Additionally, they form secondary emissions of HCN due to catalytic reactions of formaldehyde and its oxidation intermediates with NH3 . With the present components of the exhaust gas aftertreatment system the HCN emissions are not efficiently converted to non-polluting gases. The development of more advanced catalyst formulations with improved oxidation activity is mandatory to solve this novel critical issue.
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Affiliation(s)
- Deniz Zengel
- Institute for Chemical Technology and Polymer ChemistryKarlsruhe Institute of TechnologyEngesserstr. 2076131KarlsruheGermany
| | - Pirmin Koch
- Institute for Chemical Technology and Polymer ChemistryKarlsruhe Institute of TechnologyEngesserstr. 2076131KarlsruheGermany
| | - Bentolhoda Torkashvand
- Institute for Chemical Technology and Polymer ChemistryKarlsruhe Institute of TechnologyEngesserstr. 2076131KarlsruheGermany
| | - Jan‐Dierk Grunwaldt
- Institute for Chemical Technology and Polymer ChemistryKarlsruhe Institute of TechnologyEngesserstr. 2076131KarlsruheGermany
| | - Maria Casapu
- Institute for Chemical Technology and Polymer ChemistryKarlsruhe Institute of TechnologyEngesserstr. 2076131KarlsruheGermany
| | - Olaf Deutschmann
- Institute for Chemical Technology and Polymer ChemistryKarlsruhe Institute of TechnologyEngesserstr. 2076131KarlsruheGermany
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33
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Huang X, Zhang G, Tang Z. Facile Fabrication of Ce/V-Modified Multi-Channel TiO 2 Nanotubes and Their Enhanced Selective Catalytic Reduction Performance. Chem Asian J 2020; 15:371-379. [PMID: 31833207 DOI: 10.1002/asia.201901535] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2019] [Revised: 12/11/2019] [Indexed: 11/10/2022]
Abstract
To optimize one-dimensional (1D) TiO2 nanofibers, tailor-made multi-channel TiO2 nanotubes have been successfully fabricated by electrospinning technology. After loading with Ce and V, the CeVTi-tube catalyst exhibited a broad working temperature window and acceptable resistance to H2 O and SO2 for elimination of NOx . The corresponding analysis revealed that the multi-channel structure provided more surface adsorbed oxygen species and that the wall of nanotubes anchored active components efficiently, which was beneficial to improve the stability as well as dispersion of the active components. Besides, a synergistic effect between Ce and V easily occurred at the CeVTi-tube catalyst, and its reducibility was significantly improved since the electron transformation between Ce and V was dramatically enhanced. Consequently, the tailor-made multi-channel CeVTi-tube catalyst exhibited satisfied de-NOx efficiency at the temperature range of 220-460 °C. It seemed that the multi-channel TiO2 nanotubes hold great potential as an excellent carrier for SCR catalysts.
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Affiliation(s)
- Xiaosheng Huang
- State Key Laboratory for Oxo Synthesis and Selective Oxidation, National Engineering Research Center for Fine Petrochemical Intermediates, Lanzhou Institute of Chemical Physics, Chinese Academy of Sciences, Lanzhou, 730000, P. R. China.,University of Chinese Academy of Sciences, Beijing, 100039, P. R. China
| | - Guodong Zhang
- State Key Laboratory for Oxo Synthesis and Selective Oxidation, National Engineering Research Center for Fine Petrochemical Intermediates, Lanzhou Institute of Chemical Physics, Chinese Academy of Sciences, Lanzhou, 730000, P. R. China
| | - Zhicheng Tang
- State Key Laboratory for Oxo Synthesis and Selective Oxidation, National Engineering Research Center for Fine Petrochemical Intermediates, Lanzhou Institute of Chemical Physics, Chinese Academy of Sciences, Lanzhou, 730000, P. R. China.,Dalian National Laboratory for Clean Energy, Dalian Institute of Chemical Physics, Chinese Academy of Sciences, Dalian, 116023, P. R. China
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34
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Huangfu L, Abubakar A, Li C, Li Y, Wang C, Yu J, Gao S. The utilization of red mud waste as industrial honeycomb catalyst for selective catalytic reduction of NO. R Soc Open Sci 2019; 6:191183. [PMID: 31827853 PMCID: PMC6894605 DOI: 10.1098/rsos.191183] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 07/10/2019] [Accepted: 10/04/2019] [Indexed: 06/10/2023]
Abstract
As a new way for the high-value utilization of red mud (RM) waste, we proposed an improved approach to prepare the RM-based sludge/powder via the sulfuric acid hydrothermal dissolution and NH3 aqueous precipitation route and then the RM-based industrial-sized honeycomb (150 × 150 × 600 mm) was successfully produced by the extrusion moulding method in pilot scale. The synthesized RM-based powdery/honeycomb catalyst exhibited more than 80% deNO x activity and good durability of H2O and SO2 above 350°C. But the decline of NO conversion was also observed above 350°C, which was confirmed to result from the increased oxygenation of NH3 at high temperature. To improve the NO conversion at high temperature, NH3 was shunted and injected into the catalyst bed at two different places (entrance and centre) to facilitate its uniform distribution, which relieved the oxidation of NH3 and increased deNO x efficiency with 98% NO conversion at 400°C. This work explored the industrial application feasibility for the RM-based honeycomb catalyst as well as the possible solution to decrease the oxygenation of NH3 at high temperature, which presented a valuable reference for the further pilot tests of RM catalyst in industry.
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Affiliation(s)
- Lin Huangfu
- State Key Laboratory of Multi-phase Complex Systems, Institute of Process Engineering, Chinese Academy of Sciences, Beijing 100190, People's Republic of China
- School of Chemistry and Chemical Engineering, University of Chinese Academy of Sciences, Beijing 100049, People's Republic of China
| | - Abdullahi Abubakar
- State Key Laboratory of Multi-phase Complex Systems, Institute of Process Engineering, Chinese Academy of Sciences, Beijing 100190, People's Republic of China
- School of Chemistry and Chemical Engineering, University of Chinese Academy of Sciences, Beijing 100049, People's Republic of China
| | - Changming Li
- State Key Laboratory of Multi-phase Complex Systems, Institute of Process Engineering, Chinese Academy of Sciences, Beijing 100190, People's Republic of China
| | - Yunjia Li
- State Key Laboratory of Multi-phase Complex Systems, Institute of Process Engineering, Chinese Academy of Sciences, Beijing 100190, People's Republic of China
- School of Chemistry and Chemical Engineering, University of Chinese Academy of Sciences, Beijing 100049, People's Republic of China
| | - Chao Wang
- School of Chemical Engineering, Xiangtan University, Xiangtan, Hunan 411105, People's Republic of China
| | - Jian Yu
- State Key Laboratory of Multi-phase Complex Systems, Institute of Process Engineering, Chinese Academy of Sciences, Beijing 100190, People's Republic of China
| | - Shiqiu Gao
- State Key Laboratory of Multi-phase Complex Systems, Institute of Process Engineering, Chinese Academy of Sciences, Beijing 100190, People's Republic of China
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35
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Ma Z, Sheng L, Wang X, Yuan W, Chen S, Xue W, Han G, Zhang Z, Yang H, Lu Y, Wang Y. Oxide Catalysts with Ultrastrong Resistance to SO 2 Deactivation for Removing Nitric Oxide at Low Temperature. Adv Mater 2019; 31:e1903719. [PMID: 31475404 DOI: 10.1002/adma.201903719] [Citation(s) in RCA: 36] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/11/2019] [Revised: 08/01/2019] [Indexed: 06/10/2023]
Abstract
Nitrogen oxides are one of the major sources of air pollution. To remove these pollutants originating from combustion of fossil fuels remains challenging in steel, cement, and glass industries as the catalysts are severely deactivated by SO2 during the low-temperature selective catalytic reduction (SCR) process. Here, a MnOX /CeO2 nanorod catalyst with outstanding resistance to SO2 deactivation is reported, which is designed based on critical information obtained from in situ transmission electron microscopy (TEM) experiments under reaction conditions and theoretical calculations. The catalysts show almost no activity loss (apparent NOX reaction rate kept unchanged at 1800 µmol g-1 h-1 ) for 1000 h test at 523 K in the presence of 200 ppm SO2 . This unprecedented performance is achieved by establishing a dynamic equilibrium between sulfates formation and decomposition over the CeO2 surface during the reactions and preventing the MnOX cluster from the steric hindrance induced by SO2 , which minimized the deactivation of the active sites of MnOX /CeO2 . This work presents the ultralong lifetime of catalysts in the presence of SO2 , along with decent activity, marking a milestone in practical applications in low-temperature selective catalytic reduction (SCR) of NOX .
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Affiliation(s)
- Zhaoxia Ma
- State Key Laboratory of Silicon Materials and School of Materials Science and Engineering, Zhejiang University, 38 Zheda Road, Hangzhou, 310027, China
| | - Liping Sheng
- State Key Laboratory of Silicon Materials and School of Materials Science and Engineering, Zhejiang University, 38 Zheda Road, Hangzhou, 310027, China
| | - Xinwei Wang
- State Key Laboratory of Silicon Materials and School of Materials Science and Engineering, Zhejiang University, 38 Zheda Road, Hangzhou, 310027, China
| | - Wentao Yuan
- State Key Laboratory of Silicon Materials and School of Materials Science and Engineering, Zhejiang University, 38 Zheda Road, Hangzhou, 310027, China
| | - Shiyuan Chen
- State Key Laboratory of Silicon Materials and School of Materials Science and Engineering, Zhejiang University, 38 Zheda Road, Hangzhou, 310027, China
| | - Wei Xue
- State Key Laboratory of Silicon Materials and School of Materials Science and Engineering, Zhejiang University, 38 Zheda Road, Hangzhou, 310027, China
| | - Gaorong Han
- State Key Laboratory of Silicon Materials and School of Materials Science and Engineering, Zhejiang University, 38 Zheda Road, Hangzhou, 310027, China
| | - Ze Zhang
- State Key Laboratory of Silicon Materials and School of Materials Science and Engineering, Zhejiang University, 38 Zheda Road, Hangzhou, 310027, China
| | - Hangsheng Yang
- State Key Laboratory of Silicon Materials and School of Materials Science and Engineering, Zhejiang University, 38 Zheda Road, Hangzhou, 310027, China
| | - Yunhao Lu
- Department of Physics, Zhejiang University, 38 Zheda Road, Hangzhou, 310027, China
| | - Yong Wang
- State Key Laboratory of Silicon Materials and School of Materials Science and Engineering, Zhejiang University, 38 Zheda Road, Hangzhou, 310027, China
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36
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Ma X, Ma Y, Li H, Tian Y. Deposition of Selective Catalytic Reduction Coating on Wire-Mesh Structure by Atmospheric Plasma Spraying. Materials (Basel) 2019; 12:E3046. [PMID: 31546896 PMCID: PMC6766329 DOI: 10.3390/ma12183046] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 07/24/2019] [Revised: 09/08/2019] [Accepted: 09/16/2019] [Indexed: 11/16/2022]
Abstract
A series of catalytic coatings consisting of MnOx-CeO2 and TiO2 support were prepared by atmospheric plasma spraying, which was aimed at the application of selective catalytic reduction (SCR) of NOx. The effect of the load of active component on the coating was firstly studied. The results showed that all the coating presented the highest catalytic activity at approximately 350 °C and the coating with the composition of 20MnOx/5CeO2/TiO2 (wt%) achieved the most powerful performance. The coating was then prepared on a wire-mesh structure substrate, which can be easily assembled as a gas filter. The results showed that the specific surface area was greatly increased resulting in the significant improvement of the catalytic activity of the coating. This strategy offered a promising possibility of removing NOx and particulate fliting simultaneously in industrial applications.
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Affiliation(s)
- Xiaoyu Ma
- College of Materials Science and Engineering, Beijing University of Technology, Beijing 100124, China.
| | - Yunlong Ma
- College of Materials Science and Engineering, Beijing University of Technology, Beijing 100124, China.
| | - Hui Li
- College of Materials Science and Engineering, Beijing University of Technology, Beijing 100124, China.
| | - Yingliang Tian
- College of Materials Science and Engineering, Beijing University of Technology, Beijing 100124, China.
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37
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Ran X, Li M, Wang K, Qian X, Fan J, Sun Y, Luo W, Teng W, Zhang WX, Yang J. Spatially Confined Tuning the Interfacial Synergistic Catalysis in Mesochannels toward Selective Catalytic Reduction. ACS Appl Mater Interfaces 2019; 11:19242-19251. [PMID: 31050880 DOI: 10.1021/acsami.9b05437] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/09/2023]
Abstract
Low-temperature selective catalytic reduction of nitrogen oxides (NO x) with NH3 (NH3-SCR) has been identified as a promising strategy to mitigate the pollution of NO x. The fine control of synergistic effect and the suppression of aggregation of the active component, however, are still the challenge because of the weak interaction between the active component and matrix. In this work, a series of Ce-promoted Mn-based heterogeneous catalysts supported on mesoporous silica (SBA-15) with different Mn contents were prepared by two separated impregnation processes. Low-temperature NH3-SCR activity demonstrates that the Mn content in the catalyst has a great influence on the activity of the NH3-SCR reaction. The 20% MnO x-CeO x/SBA-15 catalyst exhibited the best catalytic performance in a broad temperature window. Moreover, it exhibits enhanced resistance to SO2 and H2O and long-term durability during 72 h reaction. The highly dispersive active phase, the formation of solid solution, the high ratio of Ce3+, and the spatial confinement effect largely contribute to the outstanding activity and durability of the 20% MnO x-CeO x/SBA-15 catalyst. Finally, a monolithic catalyst fabricated by the 20% MnO x-CeO x/SBA-15 catalyst powder and cordierite substrate show promising industrial application.
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Affiliation(s)
- Xianqiang Ran
- College of Environmental Science and Engineering, State Key Laboratory of Pollution Control and Resources Reuse , Tongji University , Shanghai 200092 , P. R. China
- Shanghai Tongji Clearon Environmental-Protection Equipment Engineering Company, Limited , Shanghai 200092 , P. R. China
| | - Minhan Li
- State Key Laboratory for Modification of Chemical Fibers and Polymer Materials, College of Materials Science and Engineering , Donghua University , Shanghai 201620 , P. R. China
| | - Kai Wang
- State Key Laboratory for Modification of Chemical Fibers and Polymer Materials, College of Materials Science and Engineering , Donghua University , Shanghai 201620 , P. R. China
| | - Xiaoyong Qian
- State Key Laboratory for Modification of Chemical Fibers and Polymer Materials, College of Materials Science and Engineering , Donghua University , Shanghai 201620 , P. R. China
| | - Jianwei Fan
- College of Environmental Science and Engineering, State Key Laboratory of Pollution Control and Resources Reuse , Tongji University , Shanghai 200092 , P. R. China
| | - Yu Sun
- Shanghai Tongji Clearon Environmental-Protection Equipment Engineering Company, Limited , Shanghai 200092 , P. R. China
| | - Wei Luo
- State Key Laboratory for Modification of Chemical Fibers and Polymer Materials, College of Materials Science and Engineering , Donghua University , Shanghai 201620 , P. R. China
| | - Wei Teng
- College of Environmental Science and Engineering, State Key Laboratory of Pollution Control and Resources Reuse , Tongji University , Shanghai 200092 , P. R. China
| | - Wei-Xian Zhang
- College of Environmental Science and Engineering, State Key Laboratory of Pollution Control and Resources Reuse , Tongji University , Shanghai 200092 , P. R. China
| | - Jianping Yang
- State Key Laboratory for Modification of Chemical Fibers and Polymer Materials, College of Materials Science and Engineering , Donghua University , Shanghai 201620 , P. R. China
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Yan L, Gu Y, Han L, Wang P, Li H, Yan T, Kuboon S, Shi L, Zhang D. Dual Promotional Effects of TiO 2-Decorated Acid-Treated MnO x Octahedral Molecular Sieve Catalysts for Alkali-Resistant Reduction of NO x. ACS Appl Mater Interfaces 2019; 11:11507-11517. [PMID: 30817117 DOI: 10.1021/acsami.9b01291] [Citation(s) in RCA: 22] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/24/2023]
Abstract
Alkali metals generated during waste incineration in power stations are not conducive to the control of nitrogen oxide (NO x) emission. Hence, improved selective catalytic reduction of NO x with ammonia (NH3-SCR) in the presence of alkali metals is a major issue for practical NO x removal. In this work, we developed a novel TiO2-decorated acid-treated MnO x octahedral molecular sieve (OMS-5(H)@TiO2) catalyst with improved alkali-resistant NO x reduction at low temperature, and the dual promotional effects of OMS-5(H)@TiO2 catalysts were clarified. It was found that the special structure of the acid-treated MnO x octahedral molecular sieve (OMS-5(H)) was responsible for the trapping of alkali metals and high deNO x activity at low temperature. Subsequently, the decoration by TiO2 further improved the redox properties by accelerating the high ratio of Mn4+ and Oα on the surface of the highly active (OMS-5(H)@TiO2) catalyst. Moreover, a thorough mechanism study via in situ diffuse reflectance infrared Fourier transform spectroscopy (in situ DRIFTs) demonstrated that the acid treatment led to remarkable increment of acid sites, which enabled the catalyst to resist alkali metals in the form of ion exchange. Meanwhile, the decoration of TiO2 further increased the strength of the Lewis acid sites, assisting more active intermediate species to effectively take part in the deNO x reaction. Besides, a "fast SCR" process was observed to certify that the decoration of TiO2 promoted the improvement of low-temperature activity in the presence of alkali metals. The dual effects combining OMS-5(H) with TiO2 decoration in terms of alkali metal resistance and high catalytic activity at low temperature proved that the high-performance deNO x catalyst was successfully developed in this work. The work paves a way for the development of superior low-temperature SCR catalysts with improved NO x reduction efficiency in the presence of alkali metals.
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Affiliation(s)
- Lijun Yan
- Department of Chemistry, School of Environmental and Chemical Engineering, Research Center of Nano Science and Technology, College of Sciences , Shanghai University , Shanghai 200444 , P. R. China
| | - Yundong Gu
- Department of Chemistry, School of Environmental and Chemical Engineering, Research Center of Nano Science and Technology, College of Sciences , Shanghai University , Shanghai 200444 , P. R. China
| | - Lupeng Han
- Department of Chemistry, School of Environmental and Chemical Engineering, Research Center of Nano Science and Technology, College of Sciences , Shanghai University , Shanghai 200444 , P. R. China
| | - Penglu Wang
- Department of Chemistry, School of Environmental and Chemical Engineering, Research Center of Nano Science and Technology, College of Sciences , Shanghai University , Shanghai 200444 , P. R. China
| | - Hongrui Li
- Department of Chemistry, School of Environmental and Chemical Engineering, Research Center of Nano Science and Technology, College of Sciences , Shanghai University , Shanghai 200444 , P. R. China
| | - Tingting Yan
- Department of Chemistry, School of Environmental and Chemical Engineering, Research Center of Nano Science and Technology, College of Sciences , Shanghai University , Shanghai 200444 , P. R. China
| | - Sanchai Kuboon
- National Nanotechnology Center , National Science and Technology Development Agency , 111 Thailand Science Park , Khlong Luang , Pathum Thani 12120 , Thailand
| | - Liyi Shi
- Department of Chemistry, School of Environmental and Chemical Engineering, Research Center of Nano Science and Technology, College of Sciences , Shanghai University , Shanghai 200444 , P. R. China
| | - Dengsong Zhang
- Department of Chemistry, School of Environmental and Chemical Engineering, Research Center of Nano Science and Technology, College of Sciences , Shanghai University , Shanghai 200444 , P. R. China
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Fischbacher B, Lechner B, Brandstätter B. Ammonia Distribution Measurement on a Hot Gas Test Bench Applying Tomographical Optical Methods. Sensors (Basel) 2019; 19:E896. [PMID: 30795519 DOI: 10.3390/s19040896] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 01/23/2019] [Revised: 02/15/2019] [Accepted: 02/18/2019] [Indexed: 11/17/2022]
Abstract
Measuring the distribution of gas concentration is a very common problem in a variety of technological fields. Depending on the detectability of the gas, as well as the technological progress of the sector, different methods are used. In this paper, we present a device and methods to detect the ammonia concentration distribution in the exhaust system of diesel engines in order to increase the performance of the exhaust aftertreatment system. The device has been designed for usage on a hot gas test bench simulating exhaust gas conditions. It consists of multiple optical beams measuring ammonia line concentrations by applying nondispersive absorption spectroscopy in the deep ultraviolet region. The detectors consist of photodiodes allowing high sampling rates up to 3 kHz while providing a high signal-to-noise ratio. A detection limit of only 1 ppm has been achieved despite the short path length of only eight centimeters. The obtained line concentrations form an inverse problem. The methodology of the tomographic techniques is described in detail in order to best solve the inverse problem and obtain the ammonia concentration distribution images for each time step.
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40
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Kim SH, Park BC, Jeon YS, Kim YK. MnO 2 Nanowire-CeO 2 Nanoparticle Composite Catalysts for the Selective Catalytic Reduction of NO x with NH 3. ACS Appl Mater Interfaces 2018; 10:32112-32119. [PMID: 30168317 DOI: 10.1021/acsami.8b09605] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/08/2023]
Abstract
MnO x-based catalysts have been applied to the selective catalytic reduction of NO x with ammonia (NH3) owing to their high NO x removal efficiency and catalytic stability. In general, the fabrication of a variety of nanomaterials in a complex structure requires complicated processes, including heat treatment and a series of cleaning steps. In addition, MnO2 which has diverse polymorphs, exhibits different catalytic effects depending on its crystalline structure. Among them, synthesizing the ε-MnO2 phase, which functions as a nanocatalyst, has been the most difficult and has hardly been reported. Here, we report the synthesis of heterostructured composite nanocatalysts consisting of ε-MnO2 nanowires (NWs) and CeO2 nanoparticles (NPs) by applying pulsed currents sequentially. This method drastically simplifies the overall process compared to the conventional techniques. Through X-ray diffraction and transmission electron microscopy, it was confirmed that 2-3 nm of CeO2 NPs were formed on the surfaces of the ε-MnO2 NWs. The de-NO x efficiency of the nanocatalysts was analyzed in terms of content variation, specific surface area, and the elemental chemical state of the surface. A ceramic filter containing the nanocatalysts shows a high catalytic activity over the broad operating temperature range 100-400 °C. In the low-temperature region, ε-MnO2 plays a major role in determining the catalytic property, which is consistent with the Brunauer-Emmett-Teller (BET), H2 temperature-programmed reduction (TPR), and X-ray photoelectron spectroscopy (XPS) results. On the other hand, in the high-temperature region, the efficiency increases gradually as the content of CeO2 increases. The H2 TPR, NH3-temperature-programmed desorption, and XPS patterns reveal why the composite exhibits such superior characteristics in the temperature range mentioned above.
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Affiliation(s)
- Su Hyo Kim
- Department of Materials Science and Engineering , Korea University , Seoul 02841 , Republic of Korea
| | - Bum Chul Park
- Department of Materials Science and Engineering , Korea University , Seoul 02841 , Republic of Korea
| | - Yoo Sang Jeon
- Department of Materials Science and Engineering , Korea University , Seoul 02841 , Republic of Korea
| | - Young Keun Kim
- Department of Materials Science and Engineering , Korea University , Seoul 02841 , Republic of Korea
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41
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Zhao D, Wang C, Yu F, Shi Y, Cao P, Dan J, Chen K, Lv Y, Guo X, Dai B. Enhanced Oxygen Vacancies in a Two-Dimensional MnAl-Layered Double Oxide Prepared via Flash Nanoprecipitation Offers High Selective Catalytic Reduction of NO x with NH₃. Nanomaterials (Basel) 2018; 8:E620. [PMID: 30111727 PMCID: PMC6116200 DOI: 10.3390/nano8080620] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 06/21/2018] [Revised: 08/09/2018] [Accepted: 08/10/2018] [Indexed: 11/21/2022]
Abstract
A two-dimensional MnAl-layered double oxide (LDO) was obtained by flash nanoprecipitation method (FNP) and used for the selective catalytic reduction of NOx with NH₃. The MnAl-LDO (FNP) catalyst formed a particle size of 114.9 nm. Further characterization exhibited rich oxygen vacancies and strong redox property to promote the catalytic activity at low temperature. The MnAl-LDO (FNP) catalyst performed excellent NO conversion above 80% at the temperature range of 100⁻400 °C, and N₂ selectivity above 90% below 200 °C, with a gas hourly space velocity (GHSV) of 60,000 h-1, and a NO concentration of 500 ppm. The maximum NO conversion is 100% at 200 °C; when the temperature in 150⁻250 °C, the NO conversion can also reach 95%. The remarkable low-temperature catalytic performance of the MnAl-LDO (FNP) catalyst presented potential applications for controlling NO emissions on the account of the presentation of oxygen vacancies.
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Affiliation(s)
- Dan Zhao
- Key Laboratory for Green Processing of Chemical Engineering of Xinjiang Bingtuan, School of Chemistry and Chemical Engineering, Shihezi University, Shihezi 832003, China.
| | - Chao Wang
- Key Laboratory for Green Processing of Chemical Engineering of Xinjiang Bingtuan, School of Chemistry and Chemical Engineering, Shihezi University, Shihezi 832003, China.
| | - Feng Yu
- Key Laboratory for Green Processing of Chemical Engineering of Xinjiang Bingtuan, School of Chemistry and Chemical Engineering, Shihezi University, Shihezi 832003, China.
| | - Yulin Shi
- Key Laboratory for Green Processing of Chemical Engineering of Xinjiang Bingtuan, School of Chemistry and Chemical Engineering, Shihezi University, Shihezi 832003, China.
| | - Peng Cao
- Key Laboratory for Green Processing of Chemical Engineering of Xinjiang Bingtuan, School of Chemistry and Chemical Engineering, Shihezi University, Shihezi 832003, China.
| | - Jianming Dan
- Key Laboratory for Green Processing of Chemical Engineering of Xinjiang Bingtuan, School of Chemistry and Chemical Engineering, Shihezi University, Shihezi 832003, China.
| | - Kai Chen
- Key Laboratory for Green Processing of Chemical Engineering of Xinjiang Bingtuan, School of Chemistry and Chemical Engineering, Shihezi University, Shihezi 832003, China.
- State Key Laboratory of Chemical Engineering, School of Chemical Engineering, East China University of Science and Technology, Shanghai 200237, China.
| | - Yin Lv
- Key Laboratory for Green Processing of Chemical Engineering of Xinjiang Bingtuan, School of Chemistry and Chemical Engineering, Shihezi University, Shihezi 832003, China.
| | - Xuhong Guo
- Key Laboratory for Green Processing of Chemical Engineering of Xinjiang Bingtuan, School of Chemistry and Chemical Engineering, Shihezi University, Shihezi 832003, China.
- State Key Laboratory of Chemical Engineering, School of Chemical Engineering, East China University of Science and Technology, Shanghai 200237, China.
| | - Bin Dai
- Key Laboratory for Green Processing of Chemical Engineering of Xinjiang Bingtuan, School of Chemistry and Chemical Engineering, Shihezi University, Shihezi 832003, China.
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Liu K, Yu Q, Qin Q, Wang C. Selective catalytic reduction of nitric oxide with carbon monoxide over alumina-pellet-supported catalysts in the presence of excess oxygen. Environ Technol 2018; 39:1878-1885. [PMID: 28617174 DOI: 10.1080/09593330.2017.1341554] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/06/2017] [Accepted: 06/04/2017] [Indexed: 06/07/2023]
Abstract
Selective catalytic reduction of nitrogen oxides with carbon monoxide (CO-SCR) is a promising technology to remove NOx and CO simultaneously from flue gas. The thermodynamic analyses of catalytic process were performed toward four kinds of active metal oxides (CuxOy, CoxOy, MnxOy and CexOy). According to the standard Gibbs free-energy changes calculated, Mn had better resistance to oxygen than Cu, Co and Ce, while Cu and Ce had better resistance to water vapor poisoning, as active metals. Then, a series of binary- and ternary-preformed catalysts with different metal ratios were prepared by the impregnation method using Al2O3 pellets as support and tested in excess oxygen (16 vol%) atmosphere with or without SO2. The results of experiment were analyzed based on thermodynamic analyses. Results indicated that the NO conversions of Cu-Co/Al2O3 catalysts increased with the rise of reaction temperature; however, the tendency changed at 160°C for Cu-Mn/Al2O3. Besides, the NO conversions of Cu-Mn/Al2O3 were better than Cu-Co/Al2O3. The catalysts with the metal ratio of 1.5 had the best denitrification performance. Among various binary catalysts, Cu-Mn/Al2O3 with the metal ratio Cu:Mn of 1.5 showed promising activity for CO-SCR, giving nearly 90% NO conversion. Besides, the doping of Ce could inhibit the sulfur poisoning and promote the oxide of CO under experimental conditions.
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Affiliation(s)
- Kaijie Liu
- a School of Metallurgy , Northeastern University , Liaoning , People's Republic of China
| | - Qingbo Yu
- a School of Metallurgy , Northeastern University , Liaoning , People's Republic of China
| | - Qin Qin
- a School of Metallurgy , Northeastern University , Liaoning , People's Republic of China
| | - Chunpeng Wang
- b Chongqing Zongshen General Power Machine Co. Ltd. , Chongqing , People's Republic of China
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Ko KY, Park K, Lee S, Kim Y, Woo WJ, Kim D, Song JG, Park J, Kim H. Recovery Improvement for Large-Area Tungsten Diselenide Gas Sensors. ACS Appl Mater Interfaces 2018; 10:23910-23917. [PMID: 29932675 DOI: 10.1021/acsami.8b07034] [Citation(s) in RCA: 35] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
Abstract
Semiconducting two-dimensional transition-metal dichalcogenides are considered promising gas-sensing materials because of their large surface-to-volume ratio, excellent electrical conductivity, and susceptible surfaces. However, enhancement of the recovery performance has not yet been intensively explored. In this study, a large-area uniform WSe2 is synthesized for use in a high-performance semiconductor gas sensor. At room temperature, the WSe2 gas sensor shows a significantly high response (4140%) to NO2 compared to the use of NH3, CO2, and acetone. This paper demonstrates improved recovery of the WSe2 gas sensor's NO2-sensing performance by utilizing external thermal energy. In addition, a novel strategy for improving the recovery of the WSe2 gas sensor is realized by reacting NH3 and adsorbed NO2 on the surface of WSe2: the NO2 molecules are spontaneously desorbed, and the recovery time is dramatically decreased (85 min → 43 s). It is expected that the fast recovery of the WSe2 gas sensor achieved here will be used to develop an environmental monitoring system platform.
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Affiliation(s)
- Kyung Yong Ko
- School of Electrical and Electronic Engineering , Yonsei University , 50 Yonsei-Ro , Seodaemun-gu, Seoul 03722 , Republic of Korea
| | - Kyunam Park
- School of Electrical and Electronic Engineering , Yonsei University , 50 Yonsei-Ro , Seodaemun-gu, Seoul 03722 , Republic of Korea
| | - Sangyoon Lee
- School of Electrical and Electronic Engineering , Yonsei University , 50 Yonsei-Ro , Seodaemun-gu, Seoul 03722 , Republic of Korea
| | - Youngjun Kim
- School of Electrical and Electronic Engineering , Yonsei University , 50 Yonsei-Ro , Seodaemun-gu, Seoul 03722 , Republic of Korea
| | - Whang Je Woo
- School of Electrical and Electronic Engineering , Yonsei University , 50 Yonsei-Ro , Seodaemun-gu, Seoul 03722 , Republic of Korea
| | - Donghyun Kim
- School of Electrical and Electronic Engineering , Yonsei University , 50 Yonsei-Ro , Seodaemun-gu, Seoul 03722 , Republic of Korea
| | - Jeong-Gyu Song
- School of Electrical and Electronic Engineering , Yonsei University , 50 Yonsei-Ro , Seodaemun-gu, Seoul 03722 , Republic of Korea
| | - Jusang Park
- School of Electrical and Electronic Engineering , Yonsei University , 50 Yonsei-Ro , Seodaemun-gu, Seoul 03722 , Republic of Korea
| | - Hyungjun Kim
- School of Electrical and Electronic Engineering , Yonsei University , 50 Yonsei-Ro , Seodaemun-gu, Seoul 03722 , Republic of Korea
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44
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Anthonysamy SBI, Afandi SB, Khavarian M, Mohamed ARB. A review of carbon-based and non-carbon-based catalyst supports for the selective catalytic reduction of nitric oxide. Beilstein J Nanotechnol 2018; 9:740-761. [PMID: 29600136 PMCID: PMC5852466 DOI: 10.3762/bjnano.9.68] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/30/2017] [Accepted: 01/18/2018] [Indexed: 05/03/2023]
Abstract
Various types of carbon-based and non-carbon-based catalyst supports for nitric oxide (NO) removal through selective catalytic reduction (SCR) with ammonia are examined in this review. A number of carbon-based materials, such as carbon nanotubes (CNTs), activated carbon (AC), and graphene (GR) and non-carbon-based materials, such as Zeolite Socony Mobil-5 (ZSM-5), TiO2, and Al2O3 supported materials, were identified as the most up-to-date and recently used catalysts for the removal of NO gas. The main focus of this review is the study of catalyst preparation methods, as this is highly correlated to the behaviour of NO removal. The general mechanisms involved in the system, the Langmuir-Hinshelwood or Eley-Riedeal mechanism, are also discussed. Characterisation analysis affecting the surface and chemical structure of the catalyst is also detailed in this work. Finally, a few major conclusions are drawn and future directions for work on the advancement of the SCR-NH3 catalyst are suggested.
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Affiliation(s)
| | - Syahidah Binti Afandi
- School of Chemical Engineering, Universiti Sains Malaysia, Engineering Campus, 14300 Nibong Tebal, Penang, Malaysia
| | - Mehrnoush Khavarian
- School of Chemical Engineering, Universiti Sains Malaysia, Engineering Campus, 14300 Nibong Tebal, Penang, Malaysia
| | - Abdul Rahman Bin Mohamed
- School of Chemical Engineering, Universiti Sains Malaysia, Engineering Campus, 14300 Nibong Tebal, Penang, Malaysia
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Wang T, Zhu C, Liu H, Xu Y, Zou X, Xu B, Chen T. Performance of selective catalytic reduction of NO with NH 3 over natural manganese ore catalysts at low temperature. Environ Technol 2018; 39:317-326. [PMID: 28278084 DOI: 10.1080/09593330.2017.1300190] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/20/2016] [Accepted: 02/02/2017] [Indexed: 06/06/2023]
Abstract
Natural manganese ore catalysts for selective catalytic reduction (SCR) of NO with NH3 at low temperature in the presence and absence of SO2 and H2O were systematically investigated. The physical and chemical properties of catalysts were characterized by X-ray diffraction, Brunauer-Emmett-Teller (BET) specific surface area, NH3 temperature-programmed desorption (NH3-TPD) and NO-TPD methods. The results showed that natural manganese ore from Qingyang of Anhui Province had a good low-temperature activity and N2 selectivity, and it could be a novel catalyst in terms of stability, good efficiency, good reusability and lower cost. The NO conversion exceeded 85% between 150°C and 300°C when the initial NO concentration was 1000 ppm. The activity was suppressed by adding H2O (10%) or SO2 (100 or 200 ppm), respectively, and its activity could recover while the SO2 supply is cut off. The simultaneous addition of H2O and SO2 led to the increase of about 100% in SCR activity than bare addition of SO2. The formation of the amorphous MnOx, high concentration of lattice oxygen and surface-adsorbed oxygen groups and a lot of reducible species as well as adsorption of the reactants brought about excellent SCR performance and exhibited good SO2 and H2O resistance.
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Affiliation(s)
- Tao Wang
- a School of Resource and Environmental Engineering , Hefei University of Technology , Hefei , People's Republic of China
- b Institute of Atmospheric Environment and Pollution Control , Hefei University of Technology , Hefei , People's Republic of China
| | - Chengzhu Zhu
- a School of Resource and Environmental Engineering , Hefei University of Technology , Hefei , People's Republic of China
- b Institute of Atmospheric Environment and Pollution Control , Hefei University of Technology , Hefei , People's Republic of China
| | - Haibo Liu
- a School of Resource and Environmental Engineering , Hefei University of Technology , Hefei , People's Republic of China
| | - Yongpeng Xu
- a School of Resource and Environmental Engineering , Hefei University of Technology , Hefei , People's Republic of China
- b Institute of Atmospheric Environment and Pollution Control , Hefei University of Technology , Hefei , People's Republic of China
| | - Xuehua Zou
- a School of Resource and Environmental Engineering , Hefei University of Technology , Hefei , People's Republic of China
| | - Bin Xu
- a School of Resource and Environmental Engineering , Hefei University of Technology , Hefei , People's Republic of China
| | - Tianhu Chen
- a School of Resource and Environmental Engineering , Hefei University of Technology , Hefei , People's Republic of China
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46
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Gholami R, Stere CE, Goguet A, Hardacre C. Non-thermal-plasma-activated de-NO x catalysis. Philos Trans A Math Phys Eng Sci 2018; 376:rsta.2017.0054. [PMID: 29175870 PMCID: PMC5719217 DOI: 10.1098/rsta.2017.0054] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Accepted: 10/03/2017] [Indexed: 06/07/2023]
Abstract
The combination of non-thermal plasma (NTP) with catalyst systems as an alternative technology to remove NOx emissions in the exhaust of lean-burn stationary and mobile sources is reviewed. Several factors, such as low exhaust gas temperatures (below 300°C), low selectivity to N2 and the presence of impurities, make current thermally activated technologies inefficient. Various hybrid plasma-catalyst systems have been examined and shown to have a synergistic effect on de-NOx efficiency when compared with NTP or catalyst-alone systems. The NTP is believed to form oxygenated species, such as aldehydes and nitrogen-containing organic species, and to convert NO to NO2, which improves the reduction efficiency of N2 during hydrocarbon-selective catalytic reduction reactions. The NTP has been used as a pretreatment to convert NO to its higher oxidation states such as NO2 to improve NOx reduction efficiency in the subsequent processes, e.g. NH3-selective catalytic reduction. It has been applied to the lean phase of the NOx storage to improve the adsorption capacity of the catalyst by conversion of NO to NO2 Alternatively, a catalyst with high adsorption capacity is chosen and the NTP is applied to the rich phase to improve the reduction activity of the catalyst at low temperature.This article is part of a discussion meeting issue 'Providing sustainable catalytic solutions for a rapidly changing world'.
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Affiliation(s)
- Rahman Gholami
- School of Chemical Engineering and Analytical Science, The University of Manchester, Manchester M13 9PL, UK
| | - Cristina E Stere
- School of Chemical Engineering and Analytical Science, The University of Manchester, Manchester M13 9PL, UK
| | - Alexandre Goguet
- School of Chemistry and Chemical Engineering, Queen's University Belfast, David Keir Building, Belfast BT9 5AG, UK
| | - Christopher Hardacre
- School of Chemical Engineering and Analytical Science, The University of Manchester, Manchester M13 9PL, UK
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47
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Geng Y, Chen X, Yang S, Liu F, Shan W. Promotional Effects of Ti on a CeO 2-MoO 3 Catalyst for the Selective Catalytic Reduction of NO x with NH 3. ACS Appl Mater Interfaces 2017; 9:16951-16958. [PMID: 28471163 DOI: 10.1021/acsami.6b05380] [Citation(s) in RCA: 44] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Abstract
In this study, Ti was doped to CeO2-MoO3 to promote the catalytic performance for the selective catalytic reduction of NOx with NH3 (NH3-SCR). The preparation method for CeMo0.5TiaOx (a = 0, 1, 2, 5, 10) catalysts was a stepwise precipitation method. When Ti was doped, all of the Ce-Mo-Ti catalysts exhibited remarkably improved NOx conversion and N2 selectivity than the CeMo0.5Ox without Ti. The CeMo0.5Ti5Ox with excellent activity in a broad temperature range was selected as an optimal catalyst to investigate the effects of Ti addition. The formation process analysis of the CeMo0.5Ti5Ox showed that, the Mo and Ti species first precipitated together from the mixed solution with the increase of pH, and then Ce species precipitated onto the Mo-Ti precipitates. The obtained catalyst exhibited remarkably facilitated NOx and NH3 adsorption, enhanced charge imbalance, promoted redox property, and improved surface acidity, which are all important reasons for the excellent catalytic performance of an NH3-SCR catalyst.
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Affiliation(s)
- Yang Geng
- Jiangsu Key Laboratory of Chemical Pollution Control and Resources Reuse, School of Environmental and Biological Engineering, Nanjing University of Science and Technology , Nanjing 210094, People's Republic of China
| | - Xiaoling Chen
- Jiangsu Key Laboratory of Chemical Pollution Control and Resources Reuse, School of Environmental and Biological Engineering, Nanjing University of Science and Technology , Nanjing 210094, People's Republic of China
| | - Shijian Yang
- Jiangsu Key Laboratory of Chemical Pollution Control and Resources Reuse, School of Environmental and Biological Engineering, Nanjing University of Science and Technology , Nanjing 210094, People's Republic of China
| | - Fudong Liu
- Materials Sciences Division, Lawrence Berkeley National Laboratory , Berkeley, California 94720, United States
| | - Wenpo Shan
- Jiangsu Key Laboratory of Chemical Pollution Control and Resources Reuse, School of Environmental and Biological Engineering, Nanjing University of Science and Technology , Nanjing 210094, People's Republic of China
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48
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Ding S, Liu F, Shi X, Liu K, Lian Z, Xie L, He H. Significant Promotion Effect of Mo Additive on a Novel Ce-Zr Mixed Oxide Catalyst for the Selective Catalytic Reduction of NO(x) with NH3. ACS Appl Mater Interfaces 2015; 7:9497-506. [PMID: 25894854 DOI: 10.1021/acsami.5b00636] [Citation(s) in RCA: 103] [Impact Index Per Article: 11.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/24/2023]
Abstract
A novel Mo-promoted Ce-Zr mixed oxide catalyst prepared by a homogeneous precipitation method was used for the selective catalytic reduction (SCR) of NO(x) with NH3. The optimal catalyst showed high NH3-SCR activity, SO2/H2O durability, and thermal stability under test conditions. The addition of Mo inhibited growth of the CeO2 particle size, improved the redox ability, and increased the amount of surface acidity, especially the Lewis acidity, all of which were favorable for the excellent NH3-SCR performance. It is believed that the catalyst is promising for the removal of NO(x) from diesel engine exhaust.
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Affiliation(s)
- Shipeng Ding
- State Key Joint Laboratory of Environment Simulation and Pollution Control, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, 18 Shuangqing Road, Haidian District, Beijing 100085, P. R. China
| | - Fudong Liu
- State Key Joint Laboratory of Environment Simulation and Pollution Control, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, 18 Shuangqing Road, Haidian District, Beijing 100085, P. R. China
| | - Xiaoyan Shi
- State Key Joint Laboratory of Environment Simulation and Pollution Control, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, 18 Shuangqing Road, Haidian District, Beijing 100085, P. R. China
| | - Kuo Liu
- State Key Joint Laboratory of Environment Simulation and Pollution Control, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, 18 Shuangqing Road, Haidian District, Beijing 100085, P. R. China
| | - Zhihua Lian
- State Key Joint Laboratory of Environment Simulation and Pollution Control, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, 18 Shuangqing Road, Haidian District, Beijing 100085, P. R. China
| | - Lijuan Xie
- State Key Joint Laboratory of Environment Simulation and Pollution Control, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, 18 Shuangqing Road, Haidian District, Beijing 100085, P. R. China
| | - Hong He
- State Key Joint Laboratory of Environment Simulation and Pollution Control, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, 18 Shuangqing Road, Haidian District, Beijing 100085, P. R. China
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49
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Li P, Lu P, Zhai Y, Li C, Chen T, Qing R, Zhang W. Low temperature SCR of NO with catalysts prepared by modified ACF loading Mn and Ce: effects of modification method. Environ Technol 2015; 36:2390-2400. [PMID: 25799366 DOI: 10.1080/09593330.2015.1031829] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/04/2023]
Abstract
Achievement of a higher NOx conversion ratio in selective catalytic reduction (SCR) at low temperature is challenging. In this work, pure activated carbon fibres (ACFs) were modified with different ratios of H2O (g), NaOH, CO2 and HNO3, respectively (named as modified ACF). The chemical and physical properties of modified ACFs were identified by Brunauer-Emmett-Teller, X-ray diffraction, Fourier transform infrared spectroscopy and X-ray photoelectron spectroscopy methods. The NOx conversion ratio of ACF was improved from 56.1% to 82.4% at 80°C after modification with 30% (mass ratio) NaOH. These modified ACFs were further loaded with the mixture of MnO2 and CeO2 in the form of metal salt solutions (named as Mn0.5Ce0.5O2/modified ACF). The NOx conversion ratio of 30% SHACF remained similar at 80°C but was increased from 60.0% to 98.5% at 360°C after loading with Mn and Ce, which showed the best performance in SCR of NOx at low temperature. It could be seen that ACF delivered higher performance in low temperature SCR after being modified with the aforementioned reactants and further loading with metals. Based on chemical and physical characterization and the performance of the catalysts, the reasons for different performances of these catalysts in low temperature SCR are discussed.
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Affiliation(s)
- Ping Li
- a College of Environmental Science and Engineering , Hunan University , Changsha 410082 , People's Republic of China
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50
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Oh KS, Woo SI. Chemiluminescence analyzer of NO x as a high-throughput screening tool in selective catalytic reduction of NO. Sci Technol Adv Mater 2011; 12:054211. [PMID: 27877438 PMCID: PMC5074432 DOI: 10.1088/1468-6996/12/5/054211] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/16/2011] [Revised: 01/24/2012] [Accepted: 11/24/2011] [Indexed: 06/06/2023]
Abstract
A chemiluminescence-based analyzer of NO x gas species has been applied for high-throughput screening of a library of catalytic materials. The applicability of the commercial NO x analyzer as a rapid screening tool was evaluated using selective catalytic reduction of NO gas. A library of 60 binary alloys composed of Pt and Co, Zr, La, Ce, Fe or W on Al2O3 substrate was tested for the efficiency of NO x removal using a home-built 64-channel parallel and sequential tubular reactor. The NO x concentrations measured by the NO x analyzer agreed well with the results obtained using micro gas chromatography for a reference catalyst consisting of 1 wt% Pt on γ-Al2O3. Most alloys showed high efficiency at 275 °C, which is typical of Pt-based catalysts for selective catalytic reduction of NO. The screening with NO x analyzer allowed to select Pt-Ce(X) (X=1-3) and Pt-Fe(2) as the optimal catalysts for NO x removal: 73% NO x conversion was achieved with the Pt-Fe(2) alloy, which was much better than the results for the reference catalyst and the other library alloys. This study demonstrates a sequential high-throughput method of practical evaluation of catalysts for the selective reduction of NO.
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Affiliation(s)
- Kwang Seok Oh
- R&D Group Eco-Energy Team, Hyundai Engineering and Construction Co, LTD, 102-4 Mabuk-dong, Giheung-Gu, Yongin-Si, Gyeonggi-Do, 446-716, Republic of Korea
| | - Seong Ihl Woo
- Department of Chemical and Biomolecular Engineering, Center for Ultramicrochemical Process Systems (CUPS) and Graduate school of EEWS (WCU), Korea Advanced Institute of Science and Technology, 373-1 Guseong-dong, Yuseong-gu, Daejeon, 305-701, Republic of Korea
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