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Zhang L, Zhao R, Li H, Bao J, Song L, Shan W, Zhu C. Enhanced NO x reduction on CePO 4 catalysts: Cu-loading, phosphotungstic acid, and insights from In-situ DRIFTs and DFT. JOURNAL OF HAZARDOUS MATERIALS 2024; 476:135023. [PMID: 38986406 DOI: 10.1016/j.jhazmat.2024.135023] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/11/2024] [Revised: 06/04/2024] [Accepted: 06/23/2024] [Indexed: 07/12/2024]
Abstract
This study investigates the effects of varying Cu/Ce doping ratios on the NH3-SCR denitrification efficiency using Cu-HPW/CePO4 catalysts, where CePO4 serves as the support and copper-doped phosphotungstic acid (HPW) acts as the active phase. The NH3-SCR reaction mechanism was studied by In-situ Diffuse Reflectance Infrared Fourier Transform Spectroscopy (In-situ DRIFTs) and Density Functional Theory (DFT). In-situ DRIFTs were employed to delve into the intricacies of adsorption and transformation dynamics at the surface sites of catalysts. This approach furnished a robust theoretical foundation aimed at augmenting the efficacy of low-temperature denitrification catalysts. DFT calculations were used to systematically investigate the reaction pathways, intermediates, transition states, and energy barriers over the HPW structure model to complete the NH3-SCR reaction. Empirical evidence suggests that modifying the catalysts with copper substantially enhances their denitrification efficacy and extends their operational temperature spectrum. A notable initial increase in denitrification efficiency was observed with increasing levels of copper modification, followed by a decline. Within the HPW-O15H site, the NH3-SCR reaction advances through both the E-R and L-H mechanisms, encompassing processes such as NH3 adsorption, intermediate formation and transformation, and product release.
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Affiliation(s)
- Lantian Zhang
- School of Materials and Metallurgy, Inner Mongolia University of Science and Technology, Baotou, Inner Mongolia 014000, China
| | - Ran Zhao
- College of Environment and Energy, Inner Mongolia University of Science and Technology, Baotou, Inner Mongolia 014000, China; Baotou rare earth research and development center, China.
| | - Hongxia Li
- School of Materials and Metallurgy, Inner Mongolia University of Science and Technology, Baotou, Inner Mongolia 014000, China.
| | - Jinxiao Bao
- School of Materials and Metallurgy, Inner Mongolia University of Science and Technology, Baotou, Inner Mongolia 014000, China
| | - Lijun Song
- Baotou rare earth research and development center, China
| | - Wenpo Shan
- Center for Excellence in Regional Atmospheric Environment, Institute of Urban Environment, Chinese Academy of Sciences, Xiamen 361021, China
| | - Chaoyang Zhu
- School of Materials and Metallurgy, Inner Mongolia University of Science and Technology, Baotou, Inner Mongolia 014000, China
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2
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He J, Deng J, Lan T, Liu X, Shen Y, Han L, Wang J, Zhang D. Strong metal oxide-zeolite interactions during selective catalytic reduction of nitrogen oxides. JOURNAL OF HAZARDOUS MATERIALS 2024; 465:133164. [PMID: 38103292 DOI: 10.1016/j.jhazmat.2023.133164] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/30/2023] [Revised: 11/21/2023] [Accepted: 11/30/2023] [Indexed: 12/19/2023]
Abstract
In response to the stricter EU VII emission standards and the "150 ℃ challenge", selective catalytic reduction by ammonia (NH3-SCR) catalysts for motor vehicles are required to achieve high NO conversion below 200 °C. Compounding metal oxides with zeolites is an important strategy to design the low-temperature SCR catalysts. Here, we original prepared Cu-SSZ-13 @ MnGdOx (Cu-Z @ MGO), which achieved over 90% NO conversion and 95% N2 selectivity at 150 ℃. It has been demonstrated that a uniform mesoporous loaded layer of MGO grows on Cu-Z, and a recrystallization zone appears at the MGO-Cu-Z interface. We discover that the excellent low-temperature SCR activity derives from the strong metal oxide-zeolite interaction (SMZI) effects. The SMZI effects cause the anchor and high dispersion of MGO on the surface of Cu-Z. Driven by the SMZI effects, the Mn3+/Mn4+ redox cycle ensures the low and medium temperature-SCR activity and the Cu2+/Cu+ redox cycle guarantees the medium and high temperature-SCR activity. The introduction of MGO improves the reaction activity of -NH2 species adsorbed at Mn sites at 150 ℃, achieving a cycle of reduction and oxidation reactions at low temperatures. This strategy of inducing SMZI effects of metal oxides and zeolites paves a way for development of high-performance catalysts.
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Affiliation(s)
- Jiebing He
- State Key Laboratory of Advanced Special Steel, Institute of Materials, School of Materials Science and Engineering, International Joint Laboratory of Catalytic Chemistry, College of Sciences, Shanghai University, No.99 Shangda Road, Shanghai 200444, PR China
| | - Jiang Deng
- State Key Laboratory of Advanced Special Steel, Institute of Materials, School of Materials Science and Engineering, International Joint Laboratory of Catalytic Chemistry, College of Sciences, Shanghai University, No.99 Shangda Road, Shanghai 200444, PR China
| | - Tianwei Lan
- State Key Laboratory of Advanced Special Steel, Institute of Materials, School of Materials Science and Engineering, International Joint Laboratory of Catalytic Chemistry, College of Sciences, Shanghai University, No.99 Shangda Road, Shanghai 200444, PR China
| | - Xiangyu Liu
- State Key Laboratory of Advanced Special Steel, Institute of Materials, School of Materials Science and Engineering, International Joint Laboratory of Catalytic Chemistry, College of Sciences, Shanghai University, No.99 Shangda Road, Shanghai 200444, PR China
| | - Yongjie Shen
- State Key Laboratory of Advanced Special Steel, Institute of Materials, School of Materials Science and Engineering, International Joint Laboratory of Catalytic Chemistry, College of Sciences, Shanghai University, No.99 Shangda Road, Shanghai 200444, PR China
| | - Lupeng Han
- State Key Laboratory of Advanced Special Steel, Institute of Materials, School of Materials Science and Engineering, International Joint Laboratory of Catalytic Chemistry, College of Sciences, Shanghai University, No.99 Shangda Road, Shanghai 200444, PR China
| | - Junan Wang
- State Key Laboratory of Advanced Special Steel, Institute of Materials, School of Materials Science and Engineering, International Joint Laboratory of Catalytic Chemistry, College of Sciences, Shanghai University, No.99 Shangda Road, Shanghai 200444, PR China.
| | - Dengsong Zhang
- State Key Laboratory of Advanced Special Steel, Institute of Materials, School of Materials Science and Engineering, International Joint Laboratory of Catalytic Chemistry, College of Sciences, Shanghai University, No.99 Shangda Road, Shanghai 200444, PR China.
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3
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Liu H, Gao F, Ko S, Luo N, Tang X, Duan E, Yi H, Zhou Y. Low-temperature NH 3-SCR performance of a novel Chlorella@Mn composite denitrification catalyst. J Environ Sci (China) 2024; 137:271-286. [PMID: 37980014 DOI: 10.1016/j.jes.2022.12.010] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/18/2022] [Revised: 12/08/2022] [Accepted: 12/10/2022] [Indexed: 11/20/2023]
Abstract
The synthesis process of conventional Mn-based denitrification catalysts is relatively complex and expensive. In this paper, a resource application of chlorella was proposed, and a Chlorella@Mn composite denitrification catalyst was innovatively synthesized by electrostatic interaction. The Chlorella@Mn composite denitrification catalyst prepared under the optimal conditions (0.54 g/L Mn2+ concentration, 20 million chlorellas/mL concentration, 450°C calcination temperature) exhibited a well-developed pore structure and large specific surface area (122 m2/g). Compared with MnOx alone, the Chlorella@Mn composite catalyst achieved superior performance, with ∼100% NH3 selective catalytic reduction (NH3-SCR) denitrification activity at 100-225°C. The results of NH3 temperature-programmed desorption (NH3-TPD) and H2 temperature-programmed reduction (H2-TPR) showed that the catalyst had strong acid sites and good redox properties. Zeta potential testing showed that the electronegativity of the chlorella cell surface could be used to enrich with Mn2+. X-ray photoelectron spectroscopy (XPS) confirmed that Chlorella@Mn had a high content of Mn3+ and surface chemisorbed oxygen. In-situ diffuse reflectance infrared Fourier transform spectroscopy (in-situ DRIFTS) experimental results showed that both Langmuir-Hinshelwood (L-H) and Eley-Rideal (E-R) mechanisms play a role in the denitrification process on the surface of the Chlorella@Mn catalyst, where the main intermediate nitrate species is monodentate nitrite. The presence of SO2 promoted the generation and strengthening of Brønsted acid sites, but also generated more sulfate species on the surface, thereby reducing the denitrification activity of the Chlorella@Mn catalyst. The Chlorella@Mn composite catalyst had the characteristics of short preparation time, simple process and low cost, making it promising for industrial application.
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Affiliation(s)
- Hengheng Liu
- School of Energy and Environmental Engineering, University of Science and Technology Beijing, Beijing 100083, China
| | - Fengyu Gao
- School of Energy and Environmental Engineering, University of Science and Technology Beijing, Beijing 100083, China; Beijing Key Laboratory of Resource-oriented Treatment of Industrial Pollutants, Beijing 100083, China
| | - Songjin Ko
- School of Energy and Environmental Engineering, University of Science and Technology Beijing, Beijing 100083, China; Department of Chemistry, Pyongyang University of Architecture, Pyongyang, Democratic People's Republic of Korea
| | - Ning Luo
- School of Energy and Environmental Engineering, University of Science and Technology Beijing, Beijing 100083, China
| | - Xiaolong Tang
- School of Energy and Environmental Engineering, University of Science and Technology Beijing, Beijing 100083, China; Beijing Key Laboratory of Resource-oriented Treatment of Industrial Pollutants, Beijing 100083, China.
| | - Erhong Duan
- School of Environmental Science and Engineering, University of Science and Technology Hebei, Hebei 050018, China
| | - Honghong Yi
- School of Energy and Environmental Engineering, University of Science and Technology Beijing, Beijing 100083, China; Beijing Key Laboratory of Resource-oriented Treatment of Industrial Pollutants, Beijing 100083, China
| | - Yuansong Zhou
- School of Energy and Environmental Engineering, University of Science and Technology Beijing, Beijing 100083, China; Beijing Key Laboratory of Resource-oriented Treatment of Industrial Pollutants, Beijing 100083, China
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Lee S, Ha HP, Lee JH, Kim J. Uncovering the centrality of mono-dentate SO 32-/SO 42- modifiers grafted on a metal vanadate in accelerating wet NO X reduction and poison pyrolysis. JOURNAL OF HAZARDOUS MATERIALS 2023; 460:132278. [PMID: 37619273 DOI: 10.1016/j.jhazmat.2023.132278] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/16/2023] [Revised: 08/08/2023] [Accepted: 08/11/2023] [Indexed: 08/26/2023]
Abstract
NOX rarely binds with labile oxygens of catalytic solids, whose Lewis acidic (LA) species possess higher binding strengths with NH3 (ENH3) and H2O than Brönsted acidic counterparts (BA--H+; -OH), oftentimes leading to elevate energy barrier (EBARRIER) and weaken H2O tolerance, respectively. These limit NH3-assisted wet NOX reduction via Langmuir-Hinshelwood-type or Eley-Rideal (ER)-type model on LA species, while leaving ER-type analogue on BA--H+ species proper to reduce wet NOX. Given hard-to-regulate strength/amount of -OH species and occasional association between ENH3 and EBARRIER, Ni1V2O6 (Ni1) was rationally chosen as a platform to isolate mono-dentate SO32-/SO42- species for use as BA--H+ bonds via protonation to increase collision frequency (k'APP,0) alongside with disclosure of advantages of SO32-/SO42--functionalized Ni1V2O6 (Ni1-S) over Ni1 in reducing wet NOX. Ni1-S outperformed Ni1 in achieving a larger BA--H+ quantity (k'APP,0↑), increasing H2O tolerance, and elevating oxygen mobility, thus promoting NOX reduction activity/consequences under SO2-excluding gases. V2O5-WO3 composite simulating a commercial catalyst could isolate mono-dentate SO32-/SO42- species and served as a control (V2O5-WO3-S) for comparison. Ni1-S was superior to V2O5-WO3-S in evading ammonium (bi-)sulfate (AS/ABS) poison accumulation and expediting AS/ABS pyrolysis efficiency, thereby improving AS/ABS resistance under SO2-including gases, while enhancing resistance against hydro-thermal aging.
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Affiliation(s)
- Seokhyun Lee
- Extreme Materials Research Center, Korea Institute of Science and Technology, Seoul 02792, South Korea; Department of Chemical & Biological Engineering, Korea University, Seoul 02841, South Korea
| | - Heon Phil Ha
- Extreme Materials Research Center, Korea Institute of Science and Technology, Seoul 02792, South Korea
| | - Jung-Hyun Lee
- Department of Chemical & Biological Engineering, Korea University, Seoul 02841, South Korea
| | - Jongsik Kim
- Department of Chemical Engineering (Integrated Engineering Program), Kyung Hee University, Yongin 17104, South Korea.
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5
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An D, Ji J, Cheng Q, Zhao X, Cai Y, Tan W, Tong Q, Ma K, Zou W, Sun J, Tang C, Dong L. Facile H 2O-Contributed O 2 Activation Strategy over Mn-Based SCR Catalysts to Counteract SO 2 Poisoning. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2023; 57:14737-14746. [PMID: 37738479 DOI: 10.1021/acs.est.3c04314] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 09/24/2023]
Abstract
Mn-based catalysts preferred in low-temperature selective catalytic reduction (SCR) are susceptible to SO2 poisoning. The stubborn sulfates make insufficient O2 activation and result in deficient reactive oxygen species (ROS) for activating reaction molecules. H2O has long been regarded as an accomplice to SO2, hastening catalyst deactivation. However, such a negative impression of the SCR reaction was reversed by our recent research. Here, we reported a H2O contribution over Mn-based SCR catalysts to counteract SO2 poisoning through accessible O2 activation, in which O2 was synergistically activated with H2O to generate ROS for less deactivation and more expected regeneration. The resulting ROS benefited from the energetically favorable route supported by water-induced Ea reduction and was actively involved in the NH3 activation and NO oxidation process. Besides, ROS maintained high stability over the SO2 + H2O-deactivated γ-MnO2 catalyst throughout the mild thermal treatment, achieving complete regeneration of its own NO disposal ability. This strategy was proven to be universally applicable to other Mn-based catalysts.
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Affiliation(s)
- Dongqi An
- China State Key Laboratory of Pollution Control and Resource Reuse, School of Environment, Jiangsu Key Laboratory of Vehicle Emissions Control, Center of Modern Analysis, Key Laboratory of Mesoscopic Chemistry of MOE, School of Chemistry and Chemical Engineering, Nanjing University, Nanjing 210093, P. R. China
| | - Jiawei Ji
- China State Key Laboratory of Pollution Control and Resource Reuse, School of Environment, Jiangsu Key Laboratory of Vehicle Emissions Control, Center of Modern Analysis, Key Laboratory of Mesoscopic Chemistry of MOE, School of Chemistry and Chemical Engineering, Nanjing University, Nanjing 210093, P. R. China
| | - Qianni Cheng
- China State Key Laboratory of Pollution Control and Resource Reuse, School of Environment, Jiangsu Key Laboratory of Vehicle Emissions Control, Center of Modern Analysis, Key Laboratory of Mesoscopic Chemistry of MOE, School of Chemistry and Chemical Engineering, Nanjing University, Nanjing 210093, P. R. China
| | - Xin Zhao
- China State Key Laboratory of Pollution Control and Resource Reuse, School of Environment, Jiangsu Key Laboratory of Vehicle Emissions Control, Center of Modern Analysis, Key Laboratory of Mesoscopic Chemistry of MOE, School of Chemistry and Chemical Engineering, Nanjing University, Nanjing 210093, P. R. China
| | - Yandi Cai
- China State Key Laboratory of Pollution Control and Resource Reuse, School of Environment, Jiangsu Key Laboratory of Vehicle Emissions Control, Center of Modern Analysis, Key Laboratory of Mesoscopic Chemistry of MOE, School of Chemistry and Chemical Engineering, Nanjing University, Nanjing 210093, P. R. China
| | - Wei Tan
- China State Key Laboratory of Pollution Control and Resource Reuse, School of Environment, Jiangsu Key Laboratory of Vehicle Emissions Control, Center of Modern Analysis, Key Laboratory of Mesoscopic Chemistry of MOE, School of Chemistry and Chemical Engineering, Nanjing University, Nanjing 210093, P. R. China
| | - Qing Tong
- China State Key Laboratory of Pollution Control and Resource Reuse, School of Environment, Jiangsu Key Laboratory of Vehicle Emissions Control, Center of Modern Analysis, Key Laboratory of Mesoscopic Chemistry of MOE, School of Chemistry and Chemical Engineering, Nanjing University, Nanjing 210093, P. R. China
| | - Kaili Ma
- Analysis and Testing Center, Southeast University, Nanjing 211189, P. R. China
| | - Weixin Zou
- China State Key Laboratory of Pollution Control and Resource Reuse, School of Environment, Jiangsu Key Laboratory of Vehicle Emissions Control, Center of Modern Analysis, Key Laboratory of Mesoscopic Chemistry of MOE, School of Chemistry and Chemical Engineering, Nanjing University, Nanjing 210093, P. R. China
| | - Jingfang Sun
- China State Key Laboratory of Pollution Control and Resource Reuse, School of Environment, Jiangsu Key Laboratory of Vehicle Emissions Control, Center of Modern Analysis, Key Laboratory of Mesoscopic Chemistry of MOE, School of Chemistry and Chemical Engineering, Nanjing University, Nanjing 210093, P. R. China
| | - Changjin Tang
- Jiangsu Province Engineering Research Center of Environmental Risk Prevention and Emergency Response Technology, School of Environment, Nanjing Normal University, Nanjing 210023, P. R. China
| | - Lin Dong
- China State Key Laboratory of Pollution Control and Resource Reuse, School of Environment, Jiangsu Key Laboratory of Vehicle Emissions Control, Center of Modern Analysis, Key Laboratory of Mesoscopic Chemistry of MOE, School of Chemistry and Chemical Engineering, Nanjing University, Nanjing 210093, P. R. China
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6
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Selective catalytic reduction of NO with NH3 over core-shell Ce@W catalyst. J RARE EARTH 2023. [DOI: 10.1016/j.jre.2023.01.005] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/15/2023]
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7
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Xiong Y, Zhao Y, Shan W, Feng X, Cui J, Lou Z, Shao G, Dong M, Yu H. Potassium promoted Gd 0.06Co catalysts for highly efficient catalytic N 2O decomposition in presence of impurity gases at low temperature. CHEMOSPHERE 2022; 303:135257. [PMID: 35671815 DOI: 10.1016/j.chemosphere.2022.135257] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/30/2022] [Revised: 05/09/2022] [Accepted: 06/04/2022] [Indexed: 06/15/2023]
Abstract
In order to enhance the catalytic performance of the Gd-modified Co3O4 catalyst (Gd0.06Co) for the N2O decomposition, alkali metal K was introduced as the promoter by impregnating the Gd0.06Co powder with an aqueous solution of KNO3 (with K/Co ratios 0.01-0.05). With the doping of K, the catalytic activity over Gd0.06Co was significantly improved and the temperature of N2O complete decomposition was decreased from 350 °C to 300 °C. Combining the results of XPS and O2-TPD, the superior catalytic performance of the optimum catalyst K0.025Gd0.06Co was mainly owing to the synergistic effect of Gd and K, which weakened the Co-O bond and endowed the catalyst surface with much more amount of oxygen vacancies. Even under the coexist of the impurity gases, such as 5 vol% O2, 100 ppmv NO and 2 vol% H2O, the K0.025Gd0.06Co catalyst exhibited prominently better catalytic activity than Gd0.06Co and K0.025Co catalysts.
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Affiliation(s)
- Ying Xiong
- College of Chemistry, Liaoning University, Shenyang, 110036, PR China
| | - Yumei Zhao
- College of Chemistry, Liaoning University, Shenyang, 110036, PR China
| | - Weijun Shan
- College of Chemistry, Liaoning University, Shenyang, 110036, PR China
| | - Xiaogeng Feng
- College of Chemistry, Liaoning University, Shenyang, 110036, PR China
| | - Junshuo Cui
- College of Chemistry, Liaoning University, Shenyang, 110036, PR China
| | - Zhenning Lou
- College of Chemistry, Liaoning University, Shenyang, 110036, PR China
| | - Guoxiang Shao
- College of Chemistry, Liaoning University, Shenyang, 110036, PR China
| | - Min Dong
- College of Chemistry, Liaoning University, Shenyang, 110036, PR China
| | - Haibiao Yu
- College of Chemistry, Liaoning University, Shenyang, 110036, PR China.
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Doping effect of rare earth metal ions Sm3+, Nd3+ and Ce4+ on denitration performance of MnO catalyst in low temperature NH3-SCR reaction. J RARE EARTH 2022. [DOI: 10.1016/j.jre.2022.08.004] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
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9
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Enhanced Water and Sulfur Resistance by Sm3+ Modification of Ce–Mn/TiO2 for NH3-SCR. Catal Letters 2022. [DOI: 10.1007/s10562-022-04023-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/02/2022]
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10
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Yao G, Wei Y, Gui K, Ling X. Catalytic performance and reaction mechanisms of NO removal with NH 3 at low and medium temperatures on Mn-W-Sb modified siderite catalysts. J Environ Sci (China) 2022; 115:126-139. [PMID: 34969443 DOI: 10.1016/j.jes.2021.06.029] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/10/2021] [Revised: 06/23/2021] [Accepted: 06/24/2021] [Indexed: 06/14/2023]
Abstract
Iron-based catalysts have been explored for selective catalytic reduction (SCR) of NO due to environmentally benign characters and good SCR activity. Mn-W-Sb modified siderite catalysts were prepared by impregnation method based on siderite ore, and SCR performance of the catalysts was investigated. The catalysts were analyzed by X-ray diffraction, H2-temperature-programmed reduction, Brunauer-Emmett-Teller, Thermogravimetry-derivative thermogravimetry and in-situ diffused reflectance infrared Fourier transform spectroscopy (DRIFTS). The modified siderite catalysts calcined at 450°C mainly consist of Fe2O3, and added Mn, W and Sb species are amorphous. 3Mn-5W-1.5Sb-siderite catalyst has a wide temperature window of 180-360°C and good N2 selectivity at low temperatures. In-situ DRIFTS results show NH4+, coordinated NH3, NH2, NO3- species (bidentate), NO2- species (nitro, nitro-nitrito, monodentate), and adsorbed NO2 can be discovered on the surface of Mn-W-Sb modified siderite catalysts, and doping of Mn will enhance adsorbed NO2 formation by synergistic catalysis with Fe3+. In addition, the addition of Sb can inhibit sulfates formation on the surface of the catalyst in the presence of SO2 and H2O. Time-dependent in-situ DRIFTS studies also indicate that both of Lewis and Brønsted acid sites play a role in SCR of NO by ammonia at low temperatures. The mechanism of NO removal on the 3Mn-5W-1.5Sb-siderite catalyst can be discovered as a combination of Eley-Rideal and Langmuir-Hinshelwood mechanisms with three reaction pathways. The mechanism of NO, oxidized by synergistic catalysis of Fe3+ and Mn4+/3+ to form NO2 among three pathways, reveals the reason of high NOx conversion of the catalyst at medium and low temperatures.
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Affiliation(s)
- Guihuan Yao
- School of Mechanical and Power Engineering, Nanjing Tech University, Nanjing 211816, China.
| | - Yuliang Wei
- School of Energy and Environment, Southeast University, Nanjing 210096, China
| | - Keting Gui
- School of Energy and Environment, Southeast University, Nanjing 210096, China
| | - Xiang Ling
- School of Mechanical and Power Engineering, Nanjing Tech University, Nanjing 211816, China.
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Chen L, Shen Y, Wang Q, Wang X, Wang Y, Li B, Li S, Zhang S, Li W. Phosphate on ceria with controlled active sites distribution for wide temperature NH 3-SCR. JOURNAL OF HAZARDOUS MATERIALS 2022; 427:128148. [PMID: 34973577 DOI: 10.1016/j.jhazmat.2021.128148] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/15/2021] [Revised: 12/14/2021] [Accepted: 12/22/2021] [Indexed: 06/14/2023]
Abstract
Practical catalysts that work well at a wide operation window for selective catalytic reduction of NOx by NH3 (NH3-SCR) are essential for the purification of non-isothermal emission such as vehicle exhaust. However, NH3-SCR catalyst with high low-temperature performance has excellent NO activation and oxidation ability, leading inevitably to NH3-intermediates over-oxidation and N2 selectivity deterioration at high operation temperatures. By far the best performance ceria-based catalyst with a super-wide temperature window of 175-400 oC for 90% NOx conversion in ideal environment and 225-475 oC for 90% NOx conversion by addition of 50 ppm SO2 and 5% H2O is obtained via distributing phosphate over the outer of ceria. NH3 protection strategy is the key for keeping high-temperature activity. Brønsted acidity surged as the formation of P-OH network via a charge compensatory mechanism of phosphate. NH3 was prone to be captured by the surface P-OH network, forming NH4+ species, avoiding being oxidized and contributing to both low and high temperature activity. NO can also be readily absorbed and oxidized to the absorbed NO2(ad) species over phosphate as reflected by in situ DRIFTS and DFT calculation, providing a facile pathway for 'fast SCR' by reacting with NH4+ species to form N2 and H2O. The reaction followed the L-H mechanism and contributed to catalytic activity under 300 oC. This directional structure fabricate strategy helps to increases the NOx conversion and N2 selectivity under a broaden temperature window. The enriched Brønsted acid sites over phosphate treated ceria were also demonstrated to have largely suppressed SO2 adsorption, which significantly slowed down the catalyst poisoning. A dynamic equilibrium between the poisoning and regeneration process can be achieved according to the shrinking-core model for each nanosphere, leading to the excellent resistance.
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Affiliation(s)
- Liang Chen
- College of Material, Chemistry and Chemical Engineering, Key Laboratory of Organosilicon Chemistry and Material Technology, Ministry of Education, Hangzhou Normal University, Hangzhou, 311121 Zhejiang, China; 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
| | - Yao Shen
- 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
| | - Qiaoli 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
| | - 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
| | - 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
| | - 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
| | - Shihan Zhang
- College of Environment, Zhejiang University of Technology, Hangzhou 310014, China; 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.
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12
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Mechanistic insight into the promoting effect of partial substitution of Mn by Ce on N2 selectivity of MnTiO catalyst for NH3-SCR of NO. J Taiwan Inst Chem Eng 2022. [DOI: 10.1016/j.jtice.2022.104269] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
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13
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Du Y, Liu X, Liu J, Du R, Wu X. DeNO x performance enhancement of Cu-based oxides via employing a TiO 2 phase to modify LDH precursors. RSC Adv 2022; 12:10142-10153. [PMID: 35424927 PMCID: PMC8968189 DOI: 10.1039/d2ra00316c] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/16/2022] [Accepted: 03/24/2022] [Indexed: 11/21/2022] Open
Abstract
CuAl-LDO, CuAl-LDO/TiO2 and CuAl-LDO/TiO2NTs catalysts were obtained from TiO2 modified LDHs precursor which were prepared by in situ assembly method. Then catalysts were evaluated in the selective catalytic reduction of NO x with NH3(NH3-SCR), and the results showed that the CuAl-LDO/TiO2NTs catalyst exhibited preferable deNO x performance (more than 80% NO x conversion and higher than 90% N2 selectivity at a temperature range of 210-330 °C) as well as good SO2 resistance. With the aid of series of characterizations such as XRD, N2 adsorption/desorption, XPS, NH3-TPD, H2-TPR, and in situ DRIFTS, it could be concluded that, doping TiO2NTs afforded the catalyst larger specific surface area, more abundant surface chemisorption oxygen species and more excellent redox performance. Meanwhile, In situ DRIFTS evidenced that CuAl-LDO/TiO2NTs catalyst has a strong adsorption capacity for the reaction gas, which is more conducive to the progress of the SCR reaction.
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Affiliation(s)
- Yali Du
- College of Chemistry and Chemical Engineering, Jinzhong University Jinzhong 030619 P. R. China
| | - Xuezhen Liu
- College of Chemistry and Chemical Engineering, Jinzhong University Jinzhong 030619 P. R. China
- College of Chemistry and Chemical Engineering, Taiyuan University of Technology Taiyuan 030024 P. R. China +86-351-6018528 +86-351-6018528
| | - Jiangning Liu
- College of Chemistry and Chemical Engineering, Taiyuan University of Technology Taiyuan 030024 P. R. China +86-351-6018528 +86-351-6018528
| | - Rongting Du
- College of Chemistry and Chemical Engineering, Taiyuan University of Technology Taiyuan 030024 P. R. China +86-351-6018528 +86-351-6018528
| | - Xu Wu
- College of Chemistry and Chemical Engineering, Taiyuan University of Technology Taiyuan 030024 P. R. China +86-351-6018528 +86-351-6018528
- Shanxi Huadun Industrial Co., Ltd Taiyuan 030062 China
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14
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Du Y, Lu D, Liu J, Li X, Wu C, Wu X, An X. Insight into the potential application of CuO x/CeO 2 catalysts for NO removal by CO: a perspective from the morphology and crystal-plane of CeO 2. NEW J CHEM 2022. [DOI: 10.1039/d2nj03542a] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
A series of CuOx/CeO2-X were fabricated and employed as the NO + CO reaction catalysts.
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Affiliation(s)
- Yali Du
- College of Chemistry and Chemical Engineering, Jinzhong University, Jinzhong 030619, P. R. China
| | - Dong Lu
- College of Chemistry and Chemical Engineering, Taiyuan University of Technology, Taiyuan 030024, P. R. China
| | - Jiangning Liu
- College of Chemistry and Chemical Engineering, Taiyuan University of Technology, Taiyuan 030024, P. R. China
| | - Xiaodong Li
- College of Chemistry and Chemical Engineering, Jinzhong University, Jinzhong 030619, P. R. China
| | - Chaohui Wu
- College of Chemistry and Chemical Engineering, Taiyuan University of Technology, Taiyuan 030024, P. R. China
| | - Xu Wu
- College of Chemistry and Chemical Engineering, Taiyuan University of Technology, Taiyuan 030024, P. R. China
| | - Xia An
- College of Chemistry and Chemical Engineering, Taiyuan University of Technology, Taiyuan 030024, P. R. China
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15
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Research advances of rare earth catalysts for catalytic purification of vehicle exhausts − Commemorating the 100th anniversary of the birth of Academician Guangxian Xu. J RARE EARTH 2021. [DOI: 10.1016/j.jre.2021.05.001] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
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16
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The Formation of Mn-Ce Oxide Catalysts for CO Oxidation by Oxalate Route: The Role of Manganese Content. NANOMATERIALS 2021; 11:nano11040988. [PMID: 33921273 PMCID: PMC8070498 DOI: 10.3390/nano11040988] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 03/15/2021] [Revised: 04/02/2021] [Accepted: 04/07/2021] [Indexed: 11/17/2022]
Abstract
The Mn-Ce oxide catalysts active in the oxidation of CO were studied by X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), temperature-programmed reduction (TPR), transition electron microscopy (TEM), energy dispersive X-Ray (EDX), and a differential dissolution technique. The Mn-Ce catalysts were prepared by thermal decomposition of oxalates by varying the Mn:Ce ratio. The nanocrystalline oxides with a fluorite structure and particle sizes of 4–6 nm were formed. The introduction of manganese led to a reduction of the oxide particle size, a decrease in the surface area, and the formation of a MnyCe1−yO2−δ solid solution. An increase in the manganese content resulted in the formation of manganese oxides such as Mn2O3, Mn3O4, and Mn5O8. The catalytic activity as a function of the manganese content had a volcano-like shape. The best catalytic performance was exhibited by the catalyst containing ca. 50 at.% Mn due to the high specific surface area, the formation of the solid solution, and the maximum content of the solid solution.
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Zhao S, Shi JW, Niu C, Wang B, He C, Liu W, Xiao L, Ma D, Wang H, Cheng Y. FeVO 4-supported Mn–Ce oxides for the low-temperature selective catalytic reduction of NO x by NH 3. Catal Sci Technol 2021. [DOI: 10.1039/d1cy01424b] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/20/2023]
Abstract
Iron vanadate (FeVO4) nanorods are used as a carrier to support manganese (Mn) and cerium (Ce) oxides for the selective catalytic reduction (SCR) of nitrogen oxides (NOx) with NH3 for the first time.
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Affiliation(s)
- Shuqi Zhao
- State Key Laboratory of Electrical Insulation and Power Equipment, Center of Nanomaterials for Renewable Energy, School of Electrical Engineering, Xi'an Jiaotong University, Xi'an 710049, China
| | - Jian-Wen Shi
- State Key Laboratory of Electrical Insulation and Power Equipment, Center of Nanomaterials for Renewable Energy, School of Electrical Engineering, Xi'an Jiaotong University, Xi'an 710049, China
| | - Cihang Niu
- State Key Laboratory of Electrical Insulation and Power Equipment, Center of Nanomaterials for Renewable Energy, School of Electrical Engineering, Xi'an Jiaotong University, Xi'an 710049, China
| | - Baorui Wang
- State Key Laboratory of Electrical Insulation and Power Equipment, Center of Nanomaterials for Renewable Energy, School of Electrical Engineering, Xi'an Jiaotong University, Xi'an 710049, China
| | - Chi He
- Department of Environmental Science and Engineering, State Key Laboratory of Multiphase Flow in Power Engineering, School of Energy and Power Engineering, Xi'an Jiaotong University, Xi'an 710049, China
| | - Wei Liu
- Qiyuan (Xi'an) Dae Young Environmental Protection Technology Co., Ltd., Xi'an 710018, China
| | - Lei Xiao
- Qiyuan (Xi'an) Dae Young Environmental Protection Technology Co., Ltd., Xi'an 710018, China
| | - Dandan Ma
- State Key Laboratory of Electrical Insulation and Power Equipment, Center of Nanomaterials for Renewable Energy, School of Electrical Engineering, Xi'an Jiaotong University, Xi'an 710049, China
| | - Hongkang Wang
- State Key Laboratory of Electrical Insulation and Power Equipment, Center of Nanomaterials for Renewable Energy, School of Electrical Engineering, Xi'an Jiaotong University, Xi'an 710049, China
| | - Yonghong Cheng
- State Key Laboratory of Electrical Insulation and Power Equipment, Center of Nanomaterials for Renewable Energy, School of Electrical Engineering, Xi'an Jiaotong University, Xi'an 710049, China
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