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Li Z, Gao M, Lv Z, Duan R, Shan Y, Li H, He G, He H. Uncovering the Dinuclear Mechanism of NO 2-Involved NH 3-SCR over Supported V 2O 5/TiO 2 Catalysts. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2023; 57:17577-17587. [PMID: 37844285 DOI: 10.1021/acs.est.3c05070] [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: 10/18/2023]
Abstract
Commercial vanadium oxide catalysts exhibit high efficiency for the selective catalytic reduction (SCR) of NO with NH3, especially in the presence of NO2 (i.e., occurrence of fast NH3-SCR). The high-activity sites and their working principle for the fast NH3-SCR reaction, however, remain elusive. Here, by combining in situ spectroscopy, isotopic labeling experiments, and density functional theory (DFT) calculations, we demonstrate that polymeric vanadyl species act as the main active sites in the fast SCR reaction because the coupling effect of the polymeric structure alters the elementary reaction step and effectively avoids the high energy barrier of the rate-determining step over monomeric vanadyl species. This study unveils the high-activity dinuclear mechanism of the NO2-involved SCR reaction over vanadia-based catalysts and provides a fundamental basis for developing high-efficiency and low V2O5-loading SCR catalysts.
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Affiliation(s)
- Zhuocan Li
- State Key Joint Laboratory of Environment Simulation and Pollution Control, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing 100085, China
- University of Chinese Academy of Sciences, Beijing 100049, China
| | - Meng Gao
- State Key Joint Laboratory of Environment Simulation and Pollution Control, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing 100085, China
- University of Chinese Academy of Sciences, Beijing 100049, China
| | - Zhihui Lv
- State Key Joint Laboratory of Environment Simulation and Pollution Control, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing 100085, China
- University of Chinese Academy of Sciences, Beijing 100049, China
| | - Rucheng Duan
- State Key Joint Laboratory of Environment Simulation and Pollution Control, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing 100085, China
- University of Chinese Academy of Sciences, Beijing 100049, China
| | - Yulong Shan
- State Key Joint Laboratory of Environment Simulation and Pollution Control, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing 100085, China
| | - Hongwei Li
- Beijing Nuclear Magnetic Resonance Center, College of Chemistry and Molecular Engineering, Peking University, Beijing 100871, China
| | - Guangzhi He
- State Key Joint Laboratory of Environment Simulation and Pollution Control, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing 100085, 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
- University of Chinese Academy of Sciences, Beijing 100049, China
- Center for Excellence in Regional Atmospheric Environment, Institute of Urban Environment, Chinese Academy of Sciences, Xiamen 361021, China
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2
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Wu H, Liu W, Zhang X, Liu Q. A novel strategy for efficient utilization of manganese tailings: High SO 2 resistance SCR catalyst preparation and faujasite zeolite synthesis. WASTE MANAGEMENT (NEW YORK, N.Y.) 2023; 164:66-73. [PMID: 37031514 DOI: 10.1016/j.wasman.2023.03.038] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/17/2022] [Revised: 01/31/2023] [Accepted: 03/27/2023] [Indexed: 06/19/2023]
Abstract
Herein, a core-shell structure SiO2@Mn catalyst was successfully synthesized from manganese tailings for NO removal through selective catalytic reduction with ammonia at low temperature. In the presence of 10 % H2O and 100 ppm SO2, the SiO2@Mn catalyst exhibited excellent catalytic activity of 85 % NO conversion at 225 °C. This special core-shell was constructed by inert nano-SiO2 particles, which grew and encapsulated on the surface of manganese oxide, inhibiting the reaction between SO2 with MnOx and thus improving the SO2 resistance. Furthermore, a filter residue was generated in the process of catalysts preparation. Under proper hydrothermal conditions, the residue comprising of Si, Al, and O was used to synthesize high-crystallinity X-type zeolite. This process fully utilized manganese tailings and inspired for Mn-based catalysts design and X-type zeolite preparation, realizing the dual benefits of atmosphere purification and solid waste disposal.
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Affiliation(s)
- Hongli Wu
- College of Materials Science and Engineering, Chongqing University, Chongqing 400044, China; College of Environment and Ecology, Chongqing University, Chongqing 400044, China
| | - Weizao Liu
- College of Materials Science and Engineering, Chongqing University, Chongqing 400044, China.
| | - Xiaogang Zhang
- School of Materials Science and Engineering, Chongqing University of Arts and Sciences, 402160, China
| | - Qingcai Liu
- College of Materials Science and Engineering, Chongqing University, Chongqing 400044, China; College of Environment and Ecology, Chongqing University, Chongqing 400044, China.
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3
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Yeo W, Shin D, Kim MH, Han JW. Change in the Electronic Environment of the VO x Active Center via Support Modification to Enhance Hg Oxidation Activity. ACS Catal 2023. [DOI: 10.1021/acscatal.2c05520] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/06/2023]
Affiliation(s)
- Woonsuk Yeo
- Department of Chemical Engineering, Pohang University of Science and Technology (POSTECH), Pohang, Gyeongbuk 37673, Republic of Korea
| | - Dongjae Shin
- Department of Chemical Engineering, Pohang University of Science and Technology (POSTECH), Pohang, Gyeongbuk 37673, Republic of Korea
| | - Moon Hyeon Kim
- Department of Environmental Engineering, Daegu University, Gyeongsan, Gyeongbuk 38453, Republic of Korea
| | - Jeong Woo Han
- Department of Chemical Engineering, Pohang University of Science and Technology (POSTECH), Pohang, Gyeongbuk 37673, Republic of Korea
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4
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Xu G, Shan W, Yu Y, Shan Y, Wu X, Wu Y, Zhang S, He L, Shuai S, Pang H, Jiang X, Zhang H, Guo L, Wang S, Xiao FS, Meng X, Wu F, Yao D, Ding Y, Yin H, He H. Advances in emission control of diesel vehicles in China. J Environ Sci (China) 2023; 123:15-29. [PMID: 36521980 DOI: 10.1016/j.jes.2021.12.012] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2021] [Revised: 12/11/2021] [Accepted: 12/13/2021] [Indexed: 06/17/2023]
Abstract
Diesel vehicles have caused serious environmental problems in China. Hence, the Chinese government has launched serious actions against air pollution and imposed more stringent regulations on diesel vehicle emissions in the latest China VI standard. To fulfill this stringent legislation, two major technical routes, including the exhaust gas recirculation (EGR) and high-efficiency selective catalytic reduction (SCR) routes, have been developed for diesel engines. Moreover, complicated aftertreatment technologies have also been developed, including use of a diesel oxidation catalyst (DOC) for controlling carbon monoxide (CO) and hydrocarbon (HC) emissions, diesel particulate filter (DPF) for particle mass (PM) emission control, SCR for the control of NOx emission, and an ammonia slip catalyst (ASC) for the control of unreacted NH3. Due to the stringent requirements of the China VI standard, the aftertreatment system needs to be more deeply integrated with the engine system. In the future, aftertreatment technologies will need further upgrades to fulfill the requirements of the near-zero emission target for diesel vehicles.
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Affiliation(s)
- Guangyan Xu
- Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing 100085, China
| | - Wenpo Shan
- Institute of Urban Environment, Chinese Academy of Sciences, Xiamen 361021, China
| | - Yunbo Yu
- Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing 100085, China
| | - Yulong Shan
- Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing 100085, China
| | | | - Ye Wu
- Tsinghua University, Beijing 100084, China
| | | | - Liqiang He
- Tsinghua University, Beijing 100084, China
| | | | - Hailong Pang
- Army Military Transportation University, Tianjin 300161, China
| | | | - Heng Zhang
- Dongfeng Motor Corporation, Wuhan 430101, China
| | - Lei Guo
- China National Heavy Duty Truck Group Company Limited, Jinan 250000, China
| | - Shufen Wang
- China National Heavy Duty Truck Group Company Limited, Jinan 250000, China
| | | | | | - Feng Wu
- Zhejiang University, Hangzhou 310027, China
| | | | - Yan Ding
- Chinese Research Academy of Environmental Sciences, Beijing 100012, China
| | - Hang Yin
- Chinese Research Academy of Environmental Sciences, Beijing 100012, China
| | - Hong He
- Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing 100085, China; Institute of Urban Environment, Chinese Academy of Sciences, Xiamen 361021, China.
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5
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Revealing the Correlation Between Surface Acid Sites and Activity of VPO/TiO2 Catalyst. Catal Letters 2022. [DOI: 10.1007/s10562-021-03794-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/20/2022]
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6
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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. ENVIRONMENTAL SCIENCE & TECHNOLOGY 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] [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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7
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Kubota H, Toyao T, Maeno Z, Inomata Y, Murayama T, Nakazawa N, Inagaki S, Kubota Y, Shimizu KI. Analogous Mechanistic Features of NH 3-SCR over Vanadium Oxide and Copper Zeolite Catalysts. ACS Catal 2021. [DOI: 10.1021/acscatal.1c02860] [Citation(s) in RCA: 19] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Hiroe Kubota
- Institute for Catalysis, Hokkaido University, N-21, W-10, Sapporo 001-0021, Japan
| | - Takashi Toyao
- Institute for Catalysis, Hokkaido University, N-21, W-10, Sapporo 001-0021, Japan
- Elements Strategy Initiative for Catalysts and Batteries, Kyoto University, Katsura, Kyoto 615-8520, Japan
| | - Zen Maeno
- Institute for Catalysis, Hokkaido University, N-21, W-10, Sapporo 001-0021, Japan
| | - Yusuke Inomata
- Faculty of Advanced Science and Technology, Kumamoto University, 2-39-1 Kurokami, Chuo-ku, Kumamoto 860-8555, Japan
| | - Toru Murayama
- Research Center for Hydrogen Energy-Based Society, Tokyo Metropolitan University, Hachioji, Tokyo 192-0397, Japan
- Yantai Key Laboratory of Gold Catalysis and Engineering, Shandong Applied Research Center of Gold Nanotechnology (Au-SDARC), School of Chemistry & Chemical Engineering, Yantai University, Yantai 264005, China
| | - Naoto Nakazawa
- Division of Materials Science and Chemical Engineering, Yokohama National University, 79-5 Tokiwadai, Hodogaya-ku, Yokohama 240-8501, Japan
| | - Satoshi Inagaki
- Division of Materials Science and Chemical Engineering, Yokohama National University, 79-5 Tokiwadai, Hodogaya-ku, Yokohama 240-8501, Japan
| | - Yoshihiro Kubota
- Division of Materials Science and Chemical Engineering, Yokohama National University, 79-5 Tokiwadai, Hodogaya-ku, Yokohama 240-8501, Japan
| | - Ken-ichi Shimizu
- Institute for Catalysis, Hokkaido University, N-21, W-10, Sapporo 001-0021, Japan
- Elements Strategy Initiative for Catalysts and Batteries, Kyoto University, Katsura, Kyoto 615-8520, Japan
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Long Y, Su Y, Xue Y, Wu Z, Weng X. V 2O 5-WO 3/TiO 2 Catalyst for Efficient Synergistic Control of NO x and Chlorinated Organics: Insights into the Arsenic Effect. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2021; 55:9317-9325. [PMID: 34110820 DOI: 10.1021/acs.est.1c02636] [Citation(s) in RCA: 23] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/12/2023]
Abstract
Municipal solid waste incineration and the iron and steel smelting industry can simultaneously discharge NOx and chlorinated organics, particularly polychlorinated dibenzo-p-dioxins and polychlorinated dibenzofurans (PCDD/Fs). Synergistic control of these pollutants has been considered among the most cost-effective methods. This work combined experimental and computational methods to investigate the reaction characteristics of a catalytically synergistic approach and gives the first insight into the effect of arsenic (As) on the multipollutant conversion efficiency, synergistic reaction mechanism, and toxic byproduct distribution over a commercial V2O5-WO3/TiO2 catalyst. The loaded As2O3 species were shown to distinctly decrease the formation energy of an oxygen vacancy at the V-O-V site, which likely contributed to the extensive formation of more toxic polychlorinated byproducts in the synergistic reaction. The As2O5 species strongly attacked neighboring V═O sites forming the As-O-V bands. Such an interaction deactivated the deNOx reaction, but led to excessive NO being oxidized into NO2 that greatly promoted the V5+-V4+ redox cycle and in turn facilitated chlorobenzene (CB) oxidation. Subsequent density functional theory (DFT) calculation further reveals that both the As2O3 and As2O5 loadings can facilitate H2O adsorption on the V2O5-WO3/TiO2 catalyst, leading to competitive adsorption between H2O and CB, and thereby deactivate the CB oxidation with water stream.
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Affiliation(s)
- Yunpeng Long
- Key Laboratory of Environment Remediation and Ecological Health, Ministry of Education, College of Environmental and Resource Sciences, Zhejiang University, 310058 Hangzhou, P. R. China
| | - Yuetan Su
- Key Laboratory of Environment Remediation and Ecological Health, Ministry of Education, College of Environmental and Resource Sciences, Zhejiang University, 310058 Hangzhou, P. R. China
| | - Yehui Xue
- Key Laboratory of Environment Remediation and Ecological Health, Ministry of Education, College of Environmental and Resource Sciences, Zhejiang University, 310058 Hangzhou, P. R. China
| | - Zhongbiao Wu
- Key Laboratory of Environment Remediation and Ecological Health, Ministry of Education, College of Environmental and Resource Sciences, Zhejiang University, 310058 Hangzhou, P. R. China
| | - Xiaole Weng
- Key Laboratory of Environment Remediation and Ecological Health, Ministry of Education, College of Environmental and Resource Sciences, Zhejiang University, 310058 Hangzhou, P. R. China
- Zhejiang Provincial Engineering Research Center of Industrial Boiler & Furnace Flue Gas Pollution Control, ZJU-Hangzhou Global Scientific and Technological Innovation Center, 311200 Hangzhou, P. R. China
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Effect of Catalyst Crystallinity on V-Based Selective Catalytic Reduction with Ammonia. NANOMATERIALS 2021; 11:nano11061452. [PMID: 34070897 PMCID: PMC8230001 DOI: 10.3390/nano11061452] [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: 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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