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Ji X, Zhang B, Wang H, Cai Y, Liu Q, Wu K, Li D, Tan W, Liu F, Dong L. Striking Improvement of N 2 Selectivity in NH 3 Oxidation Reaction on Fe 2O 3-Based Catalysts via SiO 2 Doping. Inorg Chem 2025; 64:1389-1400. [PMID: 39805230 DOI: 10.1021/acs.inorgchem.4c04482] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/16/2025]
Abstract
The emission of NH3 has been reported to pose a serious threat to both human health and the environment. To efficiently eliminate NH3, catalysts for the selective catalytic oxidation of NH3 (NH3-SCO) have been intensively studied. Fe2O3-based catalysts were found to exhibit superior NH3 oxidation activity; however, the low N2 selectivity made it less attractive in practical applications. In this work, aimed at improving the N2 selectivity on Fe2O3-based catalysts, a simple SiO2 doping strategy was proposed. Although the NH3 oxidation activity showed almost no change on Fe2O3 after SiO2 doping, the N2 selectivity was significantly improved. Systematic characterizations revealed that SiO2 doping could increase the specific surface area of Fe2O3, and a strong interaction of Fe-O-Si was formed in Fe2O3-SiO2 mixed oxide catalysts. Furthermore, abundant Brønsted acid sites were formed on Fe2O3-SiO2 catalysts due to the facile hydrolysis of the Fe-O-Si structure into Si-OH and Fe-OH. Although SiO2 doping was found to weaken the redox ability of Fe2O3, the abundant Brønsted acid sites on Fe2O3-SiO2 catalysts could facilitate NH3 oxidation reaction through an internal SCR (i-SCR) pathway, thus achieving superior N2 selectivity. This work can provide new insights into constructing efficient NH3-SCO catalysts with high N2 selectivity.
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Affiliation(s)
- Xiaoyu Ji
- 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 210023, China
| | - Bifeng Zhang
- 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 210023, China
| | - Huaizhu Wang
- State Key Laboratory of Coordination Chemistry, MOE Key Laboratory of Mesoscopic Chemistry, MOE Key Laboratory of High Performance Polymer Materials and Technology, Jiangsu Key Laboratory of Advanced Organic Materials, School of Chemistry and Chemical Engineering, Nanjing University, Nanjing, Jiangsu 210023, China
| | - Yandi Cai
- 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 210023, China
| | - Qinglong Liu
- 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 210023, China
| | - Kaiqiang Wu
- Jiangsu Key Laboratory of Atmospheric Environment Monitoring and Pollution Control (AEMPC), Jiangsu Collaborative Innovation Center of Atmospheric Environment and Equipment Technology (CICAEET), School of Environmental Science and Engineering, Nanjing University of Information Science and Technology, Nanjing 210044, China
| | - Dawei Li
- Jiangsu Key Laboratory of Atmospheric Environment Monitoring and Pollution Control (AEMPC), Jiangsu Collaborative Innovation Center of Atmospheric Environment and Equipment Technology (CICAEET), School of Environmental Science and Engineering, Nanjing University of Information Science and Technology, Nanjing 210044, China
| | - Wei Tan
- 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 210023, China
| | - Fudong Liu
- Department of Chemical and Environmental Engineering, Bourns College of Engineering, Center for Environmental Research and Technology (CE-CERT), Materials Science and Engineering (MSE) Program, University of California, Riverside, California 92521, United States
| | - Lin Dong
- 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 210023, China
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Wei N, Hu X, Zhao C, Tong Z, Yun J, Jiang X, Wang K, Zou Y, Chen Z. Unveiling alkali metal poisoning of CrMn catalyst for selective catalytic reduction of NO x with NH 3: An experimental and theoretical study. THE SCIENCE OF THE TOTAL ENVIRONMENT 2023; 873:162294. [PMID: 36801342 DOI: 10.1016/j.scitotenv.2023.162294] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/03/2022] [Revised: 02/09/2023] [Accepted: 02/13/2023] [Indexed: 06/18/2023]
Abstract
Alkali metal poisoning has been an intricate and unsolved issue confining the catalytic activity of NH3-SCR catalysts up to now. Herein, the effect of NaCl and KCl on catalytic activity of CrMn catalyst for NH3-SCR of NOx was systematically investigated to clarify the alkali metal poisoning by combined experiments and theoretical calculations. It unveiled that NaCl/KCl could deactivate CrMn catalyst due to the decrease in specific surface area, electron transfer (Cr5++Mn3+↔Cr3++Mn4+), redox ability and oxygen vacancy and NH3/NO adsorption. In addition, NaCl cut off E-R mechanism reactions by inactivating surface Brønsted/Lewis acid sites. DFT calculations revealed that (1) Na and K could weaken MnO bond, (2) competitive adsorption between Cl and NH3 was a main reason weakening Lewis acid, (3) Cl adsorption was also a major cause diminishing Brønsted acid and oxygen vacancy, (4) Both Na and K seriously impeded NO adsorption/activation, (5) NaCl/KCl increased the reaction heat of H2O desorption (rate-determining step) in E-R mechanism reactions and KCl elevated its energy barrier in L-H mechanism reactions. Thus, this study provides the deep understanding of alkali metal poisoning and a well strategy to synthesize NH3-SCR catalysts with outstanding alkali metal resistance.
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Affiliation(s)
- Ninghan Wei
- Guangxi Key Laboratory of Petrochemical Resource Processing and Process Intensification Technology, School of Chemistry and Chemical Engineering, Guangxi University, Nanning 530004, PR China
| | - Xiaomei Hu
- Guangdong Key Lab of Water & Air Pollution Control, Guangdong Province Engineering Laboratory for Air Pollution Control, South China Institute of Environmental Sciences, Ministry of Ecology and Environment, Guangzhou 510655, PR China
| | - Cheng Zhao
- Guangdong Key Lab of Water & Air Pollution Control, Guangdong Province Engineering Laboratory for Air Pollution Control, South China Institute of Environmental Sciences, Ministry of Ecology and Environment, Guangzhou 510655, PR China
| | - Zhangfa Tong
- Guangxi Key Laboratory of Petrochemical Resource Processing and Process Intensification Technology, School of Chemistry and Chemical Engineering, Guangxi University, Nanning 530004, PR China
| | - Junge Yun
- College of Environment and Resources, Xiangtan University, Xiangtan 411105, PR China
| | - Xueying Jiang
- Guangxi Key Laboratory of Petrochemical Resource Processing and Process Intensification Technology, School of Chemistry and Chemical Engineering, Guangxi University, Nanning 530004, PR China
| | - Keju Wang
- Guangxi Key Laboratory of Petrochemical Resource Processing and Process Intensification Technology, School of Chemistry and Chemical Engineering, Guangxi University, Nanning 530004, PR China
| | - Yun Zou
- Guangxi Key Laboratory of Petrochemical Resource Processing and Process Intensification Technology, School of Chemistry and Chemical Engineering, Guangxi University, Nanning 530004, PR China.
| | - Zhihang Chen
- Guangdong Key Lab of Water & Air Pollution Control, Guangdong Province Engineering Laboratory for Air Pollution Control, South China Institute of Environmental Sciences, Ministry of Ecology and Environment, Guangzhou 510655, PR China; College of Environment and Resources, Xiangtan University, Xiangtan 411105, PR China.
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Xiong Z, Zhang Y, Yang Q, Zhou F, Lu W, Shi H, Lu S. Promotional effect of nickel doping on the W/Fe2O3 catalyst for selective catalytic reduction of NO with NH3. MOLECULAR CATALYSIS 2023. [DOI: 10.1016/j.mcat.2022.112902] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
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Xu Q, Li Z, Wang L, Zhan W, Guo Y, Guo Y. Understand the role of redox property and NO adsorption over MnFeOx for NH3-SCR. Catal Sci Technol 2022. [DOI: 10.1039/d1cy02203b] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Widening the operation temperature window of selective catalytic reduction NO by NH3 (NH3-SCR) is a challenge to meet the increasingly stringent emission control regulations of NOx. Hence, MnFeOx with different...
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Xu T, Liu X, Zhu T, Feng C, Hu Y, Tian M. New insights into the influence mechanism of H2O and SO2 on Pt-W/Ti catalysts for CO oxidation. Catal Sci Technol 2022. [DOI: 10.1039/d1cy01984h] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
A series of anatase TiO2 loaded with 0.1 wt.% Pt and n% WO3 (0.1Pt-nW/Ti-A, n=0, 1, 2, 5, 10) were prepared using the step-impregnation method. Among the catalysts, 0.1Pt-5W/Ti-A showed...
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