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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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Wang B, Feng X, Xu Y, Shi JW. Role of Ce in promoting low-temperature performance and hydrothermal stability of Ce/Cu-SSZ-13 in the selective catalytic reduction of NOx with NH3. Sep Purif Technol 2023. [DOI: 10.1016/j.seppur.2023.123679] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/29/2023]
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NH3-Selective Catalytic Reduction of NOx to N2 over Ceria Supported WOx Based Catalysts: Influence of Tungsten Content. Catalysts 2021. [DOI: 10.3390/catal11080950] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022] Open
Abstract
A series of HPW/CeO2 catalysts generated from 12-tungstophosphoric acid, H3PW12O40 (HPW), supported on ceria and presenting different tungsten loadings (2, 4.5, 9, 16, and 40 wt% W) were prepared and characterized by N2 physisorption, XRD, IR, Raman, and UV-Vis. The different characterization techniques suggested that low loading of tungsten resulted in mainly isolated sites, while high tungsten loading produced polymeric or tungsten clusters. Those materials exhibited high activity in NH3-SCR of NOx into N2. Moreover, the series of experiments indicated that low loading in tungsten (2% HPW/CeO2) displayed the highest activity with a remarkable N2 selectivity (99%) at medium-high temperature (300–515 °C), owing to the high amount of monomeric tungstate coverage on the catalyst surface.
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Jin J, Song Z, Zhang X, Mao Y. Role of silicotungstic acid on the catalytic performance over CeO
2
‐HSiW catalysts for selective catalytic reduction of NO
x
with NH
3. Appl Organomet Chem 2021. [DOI: 10.1002/aoc.6237] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Affiliation(s)
- Junjie Jin
- Henan University of Urban Construction Henan Key Laboratory of Water Pollution Control and Rehabilitation Technology Pingdingshan China
| | - Zhongxian Song
- Henan University of Urban Construction Henan Key Laboratory of Water Pollution Control and Rehabilitation Technology Pingdingshan China
| | - Xuejun Zhang
- College of Environmental and Safety Engineering Shenyang University of Chemical Technology Shenyang China
| | - Yanli Mao
- Henan University of Urban Construction Henan Key Laboratory of Water Pollution Control and Rehabilitation Technology Pingdingshan China
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Influence of CeO2 loading on structure and catalytic activity for NH3-SCR over TiO2-supported CeO2. J RARE EARTH 2020. [DOI: 10.1016/j.jre.2020.01.005] [Citation(s) in RCA: 24] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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In situ DRIFTS investigation on CeO2/TiO2–ZrO2–SO2−4 catalyst for NH3–SCR: the influence of surface acidity and reducibility. RESEARCH ON CHEMICAL INTERMEDIATES 2020. [DOI: 10.1007/s11164-019-03961-7] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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Lian Z, Shan W, Wang M, He H, Feng Q. The balance of acidity and redox capability over modified CeO 2 catalyst for the selective catalytic reduction of NO with NH 3. J Environ Sci (China) 2019; 79:273-279. [PMID: 30784451 DOI: 10.1016/j.jes.2018.11.018] [Citation(s) in RCA: 17] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/27/2018] [Revised: 11/21/2018] [Accepted: 11/22/2018] [Indexed: 06/09/2023]
Abstract
The effect of acidity and redox capability over sulfuric acid-modified CeO2 catalysts were studied for the selective catalytic reduction of NOx with NH3 (NH3-SCR). The deposition of sulfate significantly enhanced the catalytic performance over CeO2. NOx conversion over 4H2SO4/CeO2 at 230-440 °C was higher than 90%. The strong redox capability of CeO2 could result in unselective NH3 oxidation and decrease high temperatures catalytic activity and N2 selectivity. The deposition of sulfate increased the acidity and weakened the redox capability, and then increased the high temperature NOx conversion and N2 selectivity. An appropriate level of acidity also promoted the activity at 190-250 °C over ceria-based catalysts, and with further increase in the acidity, the SCR activity decreased slightly. Weak redox capability lowered the low-temperature catalytic activity. Excellent SCR activity requires a balance of acidity and redox capability on the catalysts.
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Affiliation(s)
- Zhihua Lian
- Center for Excellence in Regional Atmospheric Environment and Key Laboratory of Urban Pollutant Conversion, Institute of Urban Environment, Chinese Academy of Sciences, Xiamen 361021, China.
| | - Wenpo Shan
- Center for Excellence in Regional Atmospheric Environment and Key Laboratory of Urban Pollutant Conversion, Institute of Urban Environment, Chinese Academy of Sciences, Xiamen 361021, China
| | - Meng Wang
- Center for Excellence in Regional Atmospheric Environment and Key Laboratory of Urban Pollutant Conversion, Institute of Urban Environment, Chinese Academy of Sciences, Xiamen 361021, China
| | - Hong He
- Center for Excellence in Regional Atmospheric Environment and Key Laboratory of Urban Pollutant Conversion, Institute of Urban Environment, Chinese Academy of Sciences, Xiamen 361021, China; Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing 100085, China; University of Chinese Academy of Sciences, Beijing 100049, China.
| | - Qingcai Feng
- Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing 100085, China.
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Lian Z, Shan W, Zhang Y, Wang M, He H. Morphology-Dependent Catalytic Performance of NbOx/CeO2 Catalysts for Selective Catalytic Reduction of NOx with NH3. Ind Eng Chem Res 2018. [DOI: 10.1021/acs.iecr.8b02553] [Citation(s) in RCA: 31] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/30/2023]
Affiliation(s)
- Zhihua Lian
- Center for Excellence in Regional Atmospheric Environment and Key Laboratory of Urban Pollutant Conversion, Institute of Urban Environment, Chinese Academy of Sciences, Xiamen 361021, China
| | - Wenpo Shan
- Center for Excellence in Regional Atmospheric Environment and Key Laboratory of Urban Pollutant Conversion, Institute of Urban Environment, Chinese Academy of Sciences, Xiamen 361021, China
| | - Yan Zhang
- Center for Excellence in Regional Atmospheric Environment and Key Laboratory of Urban Pollutant Conversion, Institute of Urban Environment, Chinese Academy of Sciences, Xiamen 361021, China
| | - Meng Wang
- Center for Excellence in Regional Atmospheric Environment and Key Laboratory of Urban Pollutant Conversion, Institute of Urban Environment, Chinese Academy of Sciences, Xiamen 361021, China
| | - Hong He
- Center for Excellence in Regional Atmospheric Environment and Key Laboratory of Urban Pollutant Conversion, Institute of Urban Environment, Chinese Academy of Sciences, Xiamen 361021, China
- 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
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DRIFT Study on Promotion Effect of the Keggin Structure over V2O5-MoO3/TiO2 Catalysts for Low Temperature NH3-SCR Reaction. Catalysts 2018. [DOI: 10.3390/catal8040143] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022] Open
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The Keggin Structure: An Important Factor in Governing NH3–SCR Activity Over the V2O5–MoO3/TiO2 Catalyst. Catal Letters 2018. [DOI: 10.1007/s10562-018-2333-4] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Abstract
Abstract
Heteropolyacids and their salts have been effectively used in selective catalytic reduction because of the Keggin structure and extraordinarily strong acidity. Catalysts with and without the Keggin structure were synthesized to further investigate the effects of heteropolyoxometallate on low temperature NH3–SCR. XRD, BET, Raman, H2–TPR, NH3–TPD, FT-IR, and SO2–TPD techniques were used to characterize the physicochemical characteristics of the catalysts. Results indicate that catalysts with the Keggin structure had more surface Brönsted and Lewis acid sites, and these catalysts had significantly improved performances in the SCR reaction and in SO2 poisoning resistance.
Graphical Abstract
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