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An D, Yang S, Cheng Q, Yan W, Sun J, Zou W, Sun C, Tang C, Dong L. Water-Driven Surface Lattice Oxygen Activation in MnO 2 for Promoted Low-Temperature NH 3-SCR. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2024. [PMID: 39250812 DOI: 10.1021/acs.est.4c06313] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 09/11/2024]
Abstract
Water is ubiquitous in various heterogeneous catalytic reactions, where it can be easily adsorbed, chemically dissociated, and diffused on catalyst surfaces, inevitably influencing the catalytic process. However, the specific role of water in these reactions remains unclear. In this study, we innovatively propose that H2O-driven surface lattice oxygen activation in γ-MnO2 significantly enhances low-temperature NH3-SCR. The proton from water dissociation activates the surface lattice oxygen in γ-MnO2, giving rise to a doubling of catalytic activity (achieving 90% NO conversion at 100 °C) and remarkable stability. Comprehensive in situ characterizations and calculations reveal that spontaneous proton diffusion to the surface lattice oxygen reduces the orbital overlap between the protonated oxygen atom and its neighboring Mn atom. Consequently, the Mn-O bond is weakened and the surface lattice oxygen is effectively activated to provide excess oxygen vacancies available for converting O2 into O2-. Therefore, the redox property of Mn-H is improved, leading to enhanced NH3 oxidation-dehydrogenation and NO oxidation processes, which are crucial for low-temperature NH3-SCR. This work provides a deeper understanding and fresh perspectives on the water promotion mechanism in low-temperature NOx elimination.
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Affiliation(s)
- Dongqi An
- Jiangsu Key Laboratory of Vehicle Emissions Control, Center of Modern Analysis, State Key Laboratory of Pollution Control and Resource Reuse, School of Environment, Key Laboratory of Mesoscopic Chemistry of MOE, School of Chemistry and Chemical Engineering, Nanjing University, Nanjing 210093, P. R. China
- Sinopec (Beijing) Research Institute of Chemical Industry Co., Ltd., Beijing 100013, P. R. China
| | - Shan Yang
- Collaborative Innovation Center of Functionalized Probes for Chemical Imaging in Universities of Shandong, Shandong Provincial Key Laboratory of Clean Production of Fine Chemicals, College of Chemistry, Chemical Engineering and Materials Science, Shandong Normal University, Jinan 250014, P. R. China
| | - Qianni Cheng
- Jiangsu Key Laboratory of Vehicle Emissions Control, Center of Modern Analysis, State Key Laboratory of Pollution Control and Resource Reuse, School of Environment, Key Laboratory of Mesoscopic Chemistry of MOE, School of Chemistry and Chemical Engineering, Nanjing University, Nanjing 210093, P. R. China
| | - Wanting Yan
- Jiangsu Key Laboratory of Vehicle Emissions Control, Center of Modern Analysis, State Key Laboratory of Pollution Control and Resource Reuse, School of Environment, Key Laboratory of Mesoscopic Chemistry of MOE, School of Chemistry and Chemical Engineering, Nanjing University, Nanjing 210093, P. R. China
| | - Jingfang Sun
- Jiangsu Key Laboratory of Vehicle Emissions Control, Center of Modern Analysis, State Key Laboratory of Pollution Control and Resource Reuse, School of Environment, Key Laboratory of Mesoscopic Chemistry of MOE, School of Chemistry and Chemical Engineering, Nanjing University, Nanjing 210093, P. R. China
| | - Weixin Zou
- Jiangsu Key Laboratory of Vehicle Emissions Control, Center of Modern Analysis, State Key Laboratory of Pollution Control and Resource Reuse, School of Environment, Key Laboratory of Mesoscopic Chemistry of MOE, School of Chemistry and Chemical Engineering, Nanjing University, Nanjing 210093, P. R. China
| | - Chuanzhi Sun
- Collaborative Innovation Center of Functionalized Probes for Chemical Imaging in Universities of Shandong, Shandong Provincial Key Laboratory of Clean Production of Fine Chemicals, College of Chemistry, Chemical Engineering and Materials Science, Shandong Normal University, Jinan 250014, 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
- Jiangsu Key Laboratory of Vehicle Emissions Control, Center of Modern Analysis, State Key Laboratory of Pollution Control and Resource Reuse, School of Environment, Key Laboratory of Mesoscopic Chemistry of MOE, School of Chemistry and Chemical Engineering, Nanjing University, Nanjing 210093, P. R. China
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Lv X, Wu S, Shao S, Yan D, Xu W, Jia H, He H. Efficient Catalytic Elimination of Chlorobenzene Based on the Water Vapor-Promoting Effect within Mn-Based Catalysts: Activity Enhancement and Polychlorinated Byproduct Inhibition. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2024; 58:3985-3996. [PMID: 38357760 DOI: 10.1021/acs.est.3c09020] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/16/2024]
Abstract
Achieving no or low polychlorinated byproduct selectivity is essential for the chlorinated volatile organic compounds (CVOCs) degradation, and the positive roles of water vapor may contribute to this goal. Herein, the oxidation behaviors of chlorobenzene over typical Mn-based catalysts (MnO2 and acid-modified MnO2) under dry and humid conditions were fully explored. The results showed that the presence of water vapor significantly facilitates the deep mineralization of chlorobenzene and restrains the formation of Cl2 and dichlorobenzene. This remarkable water vapor-promoting effect was conferred by the MnO2 substrate, which could suitably synergize with the postconstructed acidic sites, leading to good activity, stability, and desirable product distribution of acid-modified MnO2 catalysts under humid conditions. A series of experiments including isotope-traced (D2O and H218O) CB-TPO provided complete insights into the direct involvement of water molecules in chlorobenzene oxidation reaction and attributed the root cause of the water vapor-promoting effect to the proton-rich environment and highly reactive water-source oxygen species rather than to the commonly assumed cleaning effect or hydrogen proton transfer processes (generation of active OOH). This work demonstrates the application potential of Mn-based catalysts in CVOCs elimination under practical application conditions (containing water vapor) and provides the guidance for the development of superior industrial catalysts.
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Affiliation(s)
- Xuelong Lv
- Xiamen Key Laboratory of Materials for Gaseous Pollutant Control, Institute of Urban Environment, Chinese Academy of Sciences, Xiamen 361021, China
- Key Laboratory of Urban Pollutant Conversion, Institute of Urban Environment, Chinese Academy of Sciences, Xiamen 361021, China
- CAS 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
| | - Shuaining Wu
- Xiamen Key Laboratory of Materials for Gaseous Pollutant Control, Institute of Urban Environment, Chinese Academy of Sciences, Xiamen 361021, China
- Key Laboratory of Urban Pollutant Conversion, Institute of Urban Environment, Chinese Academy of Sciences, Xiamen 361021, China
- CAS 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
| | - Siting Shao
- Xiamen Key Laboratory of Materials for Gaseous Pollutant Control, Institute of Urban Environment, Chinese Academy of Sciences, Xiamen 361021, China
- Key Laboratory of Urban Pollutant Conversion, Institute of Urban Environment, Chinese Academy of Sciences, Xiamen 361021, China
- CAS 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
| | - Dongxu Yan
- Xiamen Key Laboratory of Materials for Gaseous Pollutant Control, Institute of Urban Environment, Chinese Academy of Sciences, Xiamen 361021, China
- Key Laboratory of Urban Pollutant Conversion, Institute of Urban Environment, Chinese Academy of Sciences, Xiamen 361021, China
- CAS 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
| | - Wenjian Xu
- Xiamen Key Laboratory of Materials for Gaseous Pollutant Control, Institute of Urban Environment, Chinese Academy of Sciences, Xiamen 361021, China
- Key Laboratory of Urban Pollutant Conversion, Institute of Urban Environment, Chinese Academy of Sciences, Xiamen 361021, China
- CAS 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
| | - Hongpeng Jia
- Xiamen Key Laboratory of Materials for Gaseous Pollutant Control, Institute of Urban Environment, Chinese Academy of Sciences, Xiamen 361021, China
- Key Laboratory of Urban Pollutant Conversion, Institute of Urban Environment, Chinese Academy of Sciences, Xiamen 361021, China
- CAS 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
- Key Laboratory of Urban Pollutant Conversion, Institute of Urban Environment, Chinese Academy of Sciences, Xiamen 361021, China
- CAS 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
- State Key Joint Laboratory of Environment Simulation and Pollution Control, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing 100085, China
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