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Du B, Hu Y, Cheng T, Jiang Z, Wang Z, Zhu C. Low-temperature selective catalytic reduction of NO with NH 3 over an FeO x /β-MnO 2 composite. RSC Adv 2023; 13:6378-6388. [PMID: 36845597 PMCID: PMC9943891 DOI: 10.1039/d3ra00235g] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/12/2023] [Accepted: 02/13/2023] [Indexed: 02/24/2023] Open
Abstract
A series of Fe-modified β-MnO2 (FeO x /β-MnO2) composite catalysts were prepared by an impregnation method with β-MnO2 and ferro nitrate as raw materials. The structures and properties of the composites were systematically characterized and analyzed by X-ray diffraction, N2 adsorption-desorption, high-resolution electron microscopy, temperature-programmed reduction of H2, temperature-programmed desorption of NH3, and FTIR infrared spectroscopy. The deNO x activity, water resistance, and sulfur resistance of the composite catalysts were evaluated in a thermally fixed catalytic reaction system. The results indicated that the FeO x /β-MnO2 composite (Fe/Mn molar ratio of 0.3 and calcination temperature of 450 °C) had higher catalytic activity and a wider reaction temperature window compared with β-MnO2. The water resistance and sulfur resistance of the catalyst were enhanced. It reached 100% NO conversion efficiency with an initial NO concentration of 500 ppm, a gas hourly space velocity of 45 000 h-1, and a reaction temperature of 175-325 °C. The appropriate Fe/Mn molar ratio sample had a synergistic effect, affecting the morphology, redox properties, and acidic sites, and helped to improve the low-temperature NH3-SCR activity of the composite catalyst.
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Affiliation(s)
- Bo Du
- School of Resource and Environmental Engineering, Hefei University of Technology Hefei 230009 P. R. China +86 551 62901649 +86 551 62901523.,Institute of Atmospheric Environment & Pollution Control, Hefei University of Technology Hefei 230009 P. R. China.,Key Laboratory of Nanominerals and Pollution Control of Anhui Higher Education Institutes, Hefei University of Technology Hefei 230009 P. R. China
| | - Yuting Hu
- School of Resource and Environmental Engineering, Hefei University of Technology Hefei 230009 P. R. China +86 551 62901649 +86 551 62901523.,Institute of Atmospheric Environment & Pollution Control, Hefei University of Technology Hefei 230009 P. R. China.,Key Laboratory of Nanominerals and Pollution Control of Anhui Higher Education Institutes, Hefei University of Technology Hefei 230009 P. R. China
| | - Ting Cheng
- School of Resource and Environmental Engineering, Hefei University of Technology Hefei 230009 P. R. China +86 551 62901649 +86 551 62901523.,Institute of Atmospheric Environment & Pollution Control, Hefei University of Technology Hefei 230009 P. R. China.,Key Laboratory of Nanominerals and Pollution Control of Anhui Higher Education Institutes, Hefei University of Technology Hefei 230009 P. R. China
| | - Zhaozhong Jiang
- School of Resource and Environmental Engineering, Hefei University of Technology Hefei 230009 P. R. China +86 551 62901649 +86 551 62901523.,Institute of Atmospheric Environment & Pollution Control, Hefei University of Technology Hefei 230009 P. R. China.,Key Laboratory of Nanominerals and Pollution Control of Anhui Higher Education Institutes, Hefei University of Technology Hefei 230009 P. R. China
| | - Zhenzhen Wang
- School of Resource and Environmental Engineering, Hefei University of Technology Hefei 230009 P. R. China +86 551 62901649 +86 551 62901523.,Institute of Atmospheric Environment & Pollution Control, Hefei University of Technology Hefei 230009 P. R. China.,Key Laboratory of Nanominerals and Pollution Control of Anhui Higher Education Institutes, Hefei University of Technology Hefei 230009 P. R. China
| | - Chengzhu Zhu
- School of Resource and Environmental Engineering, Hefei University of Technology Hefei 230009 P. R. China +86 551 62901649 +86 551 62901523.,Institute of Atmospheric Environment & Pollution Control, Hefei University of Technology Hefei 230009 P. R. China.,Key Laboratory of Nanominerals and Pollution Control of Anhui Higher Education Institutes, Hefei University of Technology Hefei 230009 P. R. China.,Low Temperature Denitration Engineering Research Center of Anhui Province Hefei 230001 P. R. China
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Costa MJ, Gonçalves AA, Rinaldi R, Bradtmüller H, Eckert H, Ferreira EB. Highly porous niobium-containing silica glasses applied to the microwave-assisted conversion of fructose into HMF. CATAL COMMUN 2022. [DOI: 10.1016/j.catcom.2022.106577] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/04/2022] Open
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Cai T, Teng Z, Wen Y, Zhang H, Wang S, Fu X, Song L, Li M, Lv J, Zeng Q. Single-atom site catalysts for environmental remediation: Recent advances. JOURNAL OF HAZARDOUS MATERIALS 2022; 440:129772. [PMID: 35988491 DOI: 10.1016/j.jhazmat.2022.129772] [Citation(s) in RCA: 16] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/04/2022] [Revised: 08/09/2022] [Accepted: 08/11/2022] [Indexed: 06/15/2023]
Abstract
Single-atom site catalysts (SACs) can maximize the utilization of active metal species and provide an attractive way to regulate the activity and selectivity of catalytic reactions. The adjustable coordination configuration and atomic structure of SACs enable them to be an ideal candidate for revealing reaction mechanisms in various catalytic processes. The minimum use of metals and relatively tight anchoring of the metal atoms significantly reduce leaching and environmental risks. Additionally, the unique physicochemical properties of single atom sites endow SACs with superior activity in various catalytic processes for environmental remediation (ER). Generally, SACs are burgeoning and promising materials in the application of ER. However, a systematic and critical review on the mechanism and broad application of SACs-based ER is lacking. Herein, we review emerging studies applying SACs for different ERs, such as eliminating organic pollutants in water, removing volatile organic compounds, purifying automobile exhaust, and others (hydrodefluorination and disinfection). We have summarized the synthesis, characterization, reaction mechanism and structural-function relationship of SACs in ER. In addition, the perspectives and challenges of SACs for ER are also analyzed. We expect that this review can provide constructive inspiration for discoveries and applications of SACs in environmental catalysis in the future.
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Affiliation(s)
- Tao Cai
- School of Resources & Environment and Safety Engineering, University of South China, Hengyang, Hunan 421001, China
| | - Zhenzhen Teng
- College of Environmental Science and Engineering, Ocean University of China, Qingdao 266100, China
| | - Yanjun Wen
- School of Resources & Environment and Safety Engineering, University of South China, Hengyang, Hunan 421001, China
| | - Huayang Zhang
- School of Chemical Engineering and Advanced Materials, The University of Adelaide, Adelaide, SA 5005, Australia
| | - Shaobin Wang
- School of Chemical Engineering and Advanced Materials, The University of Adelaide, Adelaide, SA 5005, Australia.
| | - Xijun Fu
- School of Resources & Environment and Safety Engineering, University of South China, Hengyang, Hunan 421001, China
| | - Lu Song
- School of Resources & Environment and Safety Engineering, University of South China, Hengyang, Hunan 421001, China
| | - Mi Li
- School of Resources & Environment and Safety Engineering, University of South China, Hengyang, Hunan 421001, China
| | - Junwen Lv
- School of Resources & Environment and Safety Engineering, University of South China, Hengyang, Hunan 421001, China
| | - Qingyi Zeng
- School of Resources & Environment and Safety Engineering, University of South China, Hengyang, Hunan 421001, China.
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Catalytic Performance and Sulfur Dioxide Resistance of One-Pot Synthesized Fe-MCM-22 in Selective Catalytic Reduction of Nitrogen Oxides with Ammonia (NH3-SCR)—The Effect of Iron Content. Int J Mol Sci 2022; 23:ijms231810754. [PMID: 36142666 PMCID: PMC9501588 DOI: 10.3390/ijms231810754] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/24/2022] [Revised: 09/07/2022] [Accepted: 09/11/2022] [Indexed: 11/17/2022] Open
Abstract
The catalytic performance of Fe-catalysts in selective catalytic reduction of nitrogen oxides with ammonia (NH3-SCR) strongly depends on the nature of iron sites. Therefore, we aimed to prepare and investigate the catalytic potential of Fe-MCM-22 with various Si/Fe molar ratios in NH3-SCR. The samples were prepared by the one-pot synthesis method to provide high dispersion of iron and reduce the number of synthesis steps. We have found that the sample with the lowest concentration of Fe exhibited the highest catalytic activity of ca. 100% at 175 °C, due to the abundance of well-dispersed isolated iron species. The decrease of Si/Fe limited the formation of microporous structure and resulted in partial amorphization, formation of iron oxide clusters, and emission of N2O during the catalytic reaction. However, an optimal concentration of FexOy oligomers contributed to the decomposition of nitrous oxide within 250–400 °C. Moreover, the acidic character of the catalysts was not a key factor determining the high conversion of NO. Additionally, we conducted NH3-SCR catalytic tests over the samples after poisoning with sulfur dioxide (SO2). We observed that SO2 affected the catalytic performance mainly in the low-temperature region, due to the deposition of thermally unstable ammonium sulfates.
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Guo RT, Qin B, Wei LG, Yin TY, Zhou J, Pan WG. Recent progress of low-temperature selective catalytic reduction of NOx with NH3 over manganese oxide-based catalysts. Phys Chem Chem Phys 2022; 24:6363-6382. [DOI: 10.1039/d1cp05557g] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Selective catalytic reduction with NH3 (NH3−SCR) was the most efficient approach to mitigate the emission of nitrogen oxides (NOx). Although the conventional manganese oxide-based catalyst had gradually become a kind...
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Preparation and Performance of Cerium-Based Catalysts for Selective Catalytic Reduction of Nitrogen Oxides: A Critical Review. Catalysts 2021. [DOI: 10.3390/catal11030361] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022] Open
Abstract
Selective catalytic reduction of nitrogen oxides with NH3 (NH3-SCR) is still the most commonly used control technology for nitrogen oxides emission. Specifically, the application of rare earth materials has become more and more extensive. CeO2 was widely developed in NH3-SCR reaction due to its good redox performance, proper surface acidity and abundant resource reserves. Therefore, a large number of papers in the literature have described the research of cerium-based catalysts. This review critically summarized the development of the different components of cerium-based catalysts, and characterized the preparation methods, the catalytic performance and reaction mechanisms of the cerium-based catalysts for NH3-SCR. The purpose of this review is to highlight: (1) the modification effect of the various metal elements for cerium-based catalysts; (2) various synthesis methods of the cerium-based catalysts; and (3) the physicochemical properties of the various catalysts and clarify their relations to catalytic performances, particularly in the presence of SO2 and H2O. Finally, we hope that this work can give timely technical guidance and valuable insights for the applications of NH3-SCR in the field of NOx control.
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SO2 Poisoning and Recovery of Copper-Based Activated Carbon Catalysts for Selective Catalytic Reduction of NO with NH3 at Low Temperature. Catalysts 2020. [DOI: 10.3390/catal10121426] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022] Open
Abstract
A series of materials based on activated carbon (AC) with copper deposited in various amounts were prepared using an incipient wetness impregnation method and tested as catalysts for selective catalytic reduction of nitrogen oxides with ammonia. The samples were poisoned with SO2 and regenerated in order to analyze their susceptibility to deactivation by the harmful component of exhaust gas. NO conversion over the fresh catalyst doped with 10 wt.% of Cu reached 81% of NO conversion at 140 °C and about 90% in the temperature range of 260–300 °C. The rate of poisoning with SO2 was dependent on Cu loading, but in general, it lowered NO conversion due to the formation of (NH4)2SO4 deposits that blocked the active sites of the catalysts. After regeneration, the catalytic activity of the materials was restored and NO conversion exceeded 70% for all of the samples.
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The Enhanced Performance of N-Modified Activated Carbon Promoted with Ce in Selective Catalytic Reduction of NOx with NH3. Catalysts 2020. [DOI: 10.3390/catal10121423] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022] Open
Abstract
The goal of the study was to modify activated carbon (AC) with nitrogen groups and ceria and to test the obtained materials in low temperature selective catalytic reduction of nitrogen oxides. For that purpose, the starting AC was oxidized with HNO3 of various concentrations, modified with urea and doped with 0.5 wt.% of Ce. It was observed that the increased concentration of acid influenced the catalytic activity, since textural and surface chemistry of activated carbon was changed. The most active sample was that modified with 14 M HNO3 and it reached 96% of NO conversion at 300 °C. Additionally, the addition of Ce improved the catalytic performance of modified AC, and NO was reduced according to oxidation–reduction mechanism, characteristic for supported metal oxides. Nevertheless, the samples promoted with Ce emitted significantly higher amount of CO2 comparing to the non-promoted ones.
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Abstract
One of the most harmful compounds are nitrogen oxides. Currently, the common industrial method of nitrogen oxides emission control is selective catalytic reduction with ammonia (NH3-SCR). Among all of the recognized measures, NH3-SCR is the most effective and reaches even up to 90% of NOx conversion. The presence of the catalyst provides the surface for the reaction to proceed and lowers the activation energy. The optimum temperature of the process is in the range of 150–450 °C and the majority of the commercial installations utilize vanadium oxide (V2O5) supported on titanium oxide (TiO2) in a form of anatase, wash coated on a honeycomb monolith or deposited on a plate-like structures. In order to improve the mechanical stability and chemical resistance, the system is usually promoted with tungsten oxide (WO3) or molybdenum oxide (MoO3). The efficiency of the commercial V2O5-WO3-TiO2 catalyst of NH3-SCR, can be gradually decreased with time of its utilization. Apart from the physical deactivation, such as high temperature sintering, attrition and loss of the active elements by volatilization, the system can suffer from chemical poisoning. All of the presented deactivating agents pass for the most severe poisons of V2O5-WO3-TiO2. In order to minimize the harmful influence of H2O, SO2, alkali metals, heavy metals and halogens, a number of methods has been developed. Some of them improve the resistance to poisons and some are focused on recovery of the catalytic system. Nevertheless, since the amount of highly contaminated fuels combusted in power plants and industry gradually increases, more effective poisoning-preventing and regeneration measures are still in high demand.
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