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Cheng S, Xu F, Yang S, Zhang B, Song W, Zhu X, Tan W, Sun C, Dong L. Modulating the Activity and SO 2 Resistance of α-Fe 2O 3 Catalysts for NH 3-SCR of NO x via Crystal Facet Engineering. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2024; 58:8955-8965. [PMID: 38718175 DOI: 10.1021/acs.est.4c00276] [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: 05/22/2024]
Abstract
The development of Fe-based catalysts for the selective catalytic reduction of NOx by NH3 (NH3-SCR of NOx) has garnered significant attention due to their exceptional SO2 resistance. However, the influence of different sulfur-containing species (e.g., ferric sulfates and ammonium sulfates) on the NH3-SCR activity of Fe-based catalysts as well as its dependence on exposed crystal facets of Fe2O3 has not been revealed. This work disclosed that nanorod-like α-Fe2O3 (Fe2O3-NR) predominantly exposing (110) facet performed better than nanosheet-like α-Fe2O3 (Fe2O3-NS) predominantly exposing (001) facet in NH3-SCR reaction, due to the advantages of Fe2O3-NR in redox properties and surface acidity. Furthermore, the results of the SO2/H2O resistance test at a critical temperature of 250 °C, catalytic performance evaluations on Fe2O3-NR and Fe2O3-NS sulfated by SO2 + O2 or deposited with NH4HSO4 (ABS), and systematic characterization revealed that the reactivity of ammonium sulfates on Fe2O3 catalysts to NO(+O2) contributed to their improved catalytic performance, while ferric sulfates showed enhancing and inhibiting effects on NH3-SCR activity on Fe2O3-NR and Fe2O3-NS, respectively; despite this, Fe2O3-NR showed higher affinity for SO2 + O2. This work set a milestone in understanding the NH3-SCR reaction on Fe2O3 catalysts in the presence of SO2 from the aspect of crystal facet engineering.
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Affiliation(s)
- Siqing Cheng
- College of Chemistry, Chemical Engineering and Materials Science, Shandong Provincial Key Laboratory of Clean Production of Fine Chemicals, Institute of Materials and Clean Energy, Shandong Normal University, Jinan 250014, P. R. China
| | - Fang Xu
- College of Chemistry, Chemical Engineering and Materials Science, Shandong Provincial Key Laboratory of Clean Production of Fine Chemicals, Institute of Materials and Clean Energy, Shandong Normal University, Jinan 250014, P. R. China
| | - Shan Yang
- College of Chemistry, Chemical Engineering and Materials Science, Shandong Provincial Key Laboratory of Clean Production of Fine Chemicals, Institute of Materials and Clean Energy, Shandong Normal University, Jinan 250014, P. R. 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, P. R. China
| | - Wang Song
- 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, P. R. China
| | - Xuechen Zhu
- College of Chemistry, Chemical Engineering and Materials Science, Shandong Provincial Key Laboratory of Clean Production of Fine Chemicals, Institute of Materials and Clean Energy, Shandong Normal University, Jinan 250014, P. R. 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, P. R. China
| | - Chuanzhi Sun
- College of Chemistry, Chemical Engineering and Materials Science, Shandong Provincial Key Laboratory of Clean Production of Fine Chemicals, Institute of Materials and Clean Energy, Shandong Normal University, Jinan 250014, P. R. China
| | - 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, P. R. China
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2
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Xing J, Xue Q, Chen J, Mi J, Chen X, Shi J, Liu Z, Li J. Potential Risk of Significant N 2O Emission without Changing NO x Conversion on Commercial V 2O 5/TiO 2 Catalyst under Working Conditions. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2023; 57:21866-21875. [PMID: 38095886 DOI: 10.1021/acs.est.3c05344] [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: 12/27/2023]
Abstract
Vanadium-based catalysts play a pivotal role in the emission control of industrial NOx via selective catalytic reduction (SCR) technology. However, little attention has been paid to the potential emission of greenhouse gas N2O under complex working conditions. This work reports that a commercial V2O5/TiO2 catalyst may lead to significant N2O emission without greatly changing the outlet NOx concentration after chromium (Cr) deposition. With a Cr loading of 2 wt %, N2O concentration increased from 27.8 to 199.2 ppm at 350 °C with the value of outlet N2O/(N2O+N2) from 2.5% to 19.4%. Experimental results combined with DFT+U calculations suggest that nonselective catalytic reduction (NSCR) is the main route for N2O formation in a wide temperature range of 250 ∼ 400 °C. It is stemmed from the fact that the covalent interaction between Cr and V species on the V2O5/TiO2 surface accelerates the conversion of V4+ + Cr6+ → V5+ + Cr3+, leading to a larger proportion of surface V5+. More importantly, surface V5+ is highly related to the redox property of the V2O5/TiO2 catalyst, which is beneficial to NSCR reaction rather than the standard SCR process. The work suggests that to better inhibit the emission of greenhouse gases during the NH3-SCR process, monitoring N2O emission should be included along with the NOx concentrations, especially in complex flue gases.
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Affiliation(s)
- Jiaying Xing
- State Key Joint Laboratory of Environment Simulation and Pollution Control, School of Environment, Tsinghua University, Beijing 100084, P. R. China
| | - Qitong Xue
- State Key Joint Laboratory of Environment Simulation and Pollution Control, School of Environment, Tsinghua University, Beijing 100084, P. R. China
- State Key Laboratory of Chemical Resource Engineering, Beijing University of Chemical Technology, Beijing 100029, China
| | - Jianjun Chen
- State Key Joint Laboratory of Environment Simulation and Pollution Control, School of Environment, Tsinghua University, Beijing 100084, P. R. China
| | - Jinxing Mi
- State Key Joint Laboratory of Environment Simulation and Pollution Control, School of Environment, Tsinghua University, Beijing 100084, P. R. China
| | - Xiaoping Chen
- State Key Joint Laboratory of Environment Simulation and Pollution Control, School of Environment, Tsinghua University, Beijing 100084, P. R. China
| | - Jianqiang Shi
- State Key Joint Laboratory of Environment Simulation and Pollution Control, School of Environment, Tsinghua University, Beijing 100084, P. R. China
| | - Zhiming Liu
- State Key Laboratory of Chemical Resource Engineering, Beijing University of Chemical Technology, Beijing 100029, China
| | - Junhua Li
- State Key Joint Laboratory of Environment Simulation and Pollution Control, School of Environment, Tsinghua University, Beijing 100084, P. R. China
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3
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Zhang H, Lian Z, Lin C, Zhu Y, Shan W, He H. Insight into the mechanisms of activity promotion and SO 2 resistance over Fe-doped Ce-W oxide catalyst for NO x reduction. J Colloid Interface Sci 2023; 652:923-935. [PMID: 37634365 DOI: 10.1016/j.jcis.2023.08.129] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/13/2023] [Revised: 08/09/2023] [Accepted: 08/20/2023] [Indexed: 08/29/2023]
Abstract
Ceria-based catalysts for the selective catalytic reduction of NOx with NH3 (NH3-SCR) are always subject to deactivation by sulfur poisoning. In this study, Fe-doped Ce-W mixed oxides, which were synthesized by the co-precipitation method, improved the SCR activity and SO2 durability at low temperatures of undoped Ce-W oxides. The improved low-temperature activity was mainly due to the enhancement of redox properties at low temperatures and more active oxygen species, together with the adsorption and activation of more abundant NOx species, facilitating the "fast SCR" reaction. In the presence of SO2, doping with Fe species effectively prevented sulfate deposition on the CeW catalyst, due to the interaction between Fe, Ce, and W species inducing electron transfer among different metal sites and altering the electron distribution. The competitive adsorption behavior between NO and SO2 was changed by Fe doping, in which the adsorption and oxidation of SO2 were restrained. Besides, the elevated NO oxidation accelerated the decomposition of ammonium bisulfate, causing the SCR reaction to not be greatly suppressed. Hence, Fe-doped Ce-W oxides catalysts showed excellent sulfur resistance. This study provides an in-depth understanding of efficient Ce-based catalysts for SO2-tolerance strategies.
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Affiliation(s)
- Hui 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; University of Chinese Academy of Sciences, Beijing 100049, China
| | - 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.
| | - Chunxi Lin
- 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; University of Chinese Academy of Sciences, Beijing 100049, China
| | - Ying Zhu
- 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; University of Chinese Academy of Sciences, Beijing 100049, 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; Zhejiang Key Laboratory of Urban Environmental Processes and Pollution Control, Ningbo Urban Environment Observation and Research Station, Institute of Urban Environment, Chinese Academy of Sciences, Ningbo 315800, 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; 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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4
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Yan Q, Xiao J, Gui R, Chen Z, Li Y, Zhu T, Wang Q, Xin Y. Mechanistic Insight into the Promotion of the Low-Temperature NH 3-SCR Activity over NiMnFeO x LDO Catalysts: A Combined Experimental and DFT Study. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2023; 57:20708-20717. [PMID: 38032314 DOI: 10.1021/acs.est.3c06849] [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: 12/01/2023]
Abstract
Mn-based catalysts have attracted much attention in the field of the low-temperature NH3 selective catalytic reduction (NH3-SCR) of NO. However, their poor SO2 resistance, low N2 selectivity, and narrow operation window limit the industrial application of Mn-based oxide catalysts. In this work, NiMnFeOx catalysts were prepared by the layered double hydroxide (LDH)-derived oxide method, and the optimized Ni0.5Mn0.5Fe0.5Ox catalyst had the best denitration activity, excellent N2 selectivity, a wider active temperature range (100-250 °C), higher thermal stability, and better H2O and/or SO2 resistance. A transient reaction revealed that Ni0.5Mn0.5Fe0.5Ox inhibited the NH3 + O2 + NOx pathway to generate N2O, which may be the main reason for its improved N2 selectivity. Combining experimental measurements and density functional theory (DFT) calculations, we elucidated at the atomic level that sulfated NiMnFeOx (111) induces the adjustment of the acidity/basicity of up and down spins and the ligand field reconfiguration of the Mn sites, which improves the overall reactivity of NiMnFeOx catalysts. This work provides atomic-level insights into the promotion of NH3-SCR activity by NiMnFeOx composite oxides, which are important for the practical design of future low-temperature SCR technologies.
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Affiliation(s)
- Qinghua Yan
- Qingdao Engineering Research Center for Rural Environment, College of Resources and Environment, Qingdao Agricultural University, Qingdao 266109, P.R. China
| | - Jiewen Xiao
- College of Environmental Science and Engineering, Beijing Forestry University, 35 Qinghua East Road, Haidian District, Beijing 100083, P.R. China
| | - Rongrong Gui
- College of Environmental Science and Engineering, Beijing Forestry University, 35 Qinghua East Road, Haidian District, Beijing 100083, P.R. China
| | - Zhenyu Chen
- Qingdao Engineering Research Center for Rural Environment, College of Resources and Environment, Qingdao Agricultural University, Qingdao 266109, P.R. China
| | - Yuran Li
- Research Center for Process Pollution Control, National Engineering Laboratory for Hydrometallurgical Cleaner Production Technology, Institute of Process Engineering, Chinese Academy of Sciences, Beijing 100190, China
| | - Tingyu Zhu
- Research Center for Process Pollution Control, National Engineering Laboratory for Hydrometallurgical Cleaner Production Technology, Institute of Process Engineering, Chinese Academy of Sciences, Beijing 100190, China
| | - Qiang Wang
- College of Environmental Science and Engineering, Beijing Forestry University, 35 Qinghua East Road, Haidian District, Beijing 100083, P.R. China
| | - Yanjun Xin
- Qingdao Engineering Research Center for Rural Environment, College of Resources and Environment, Qingdao Agricultural University, Qingdao 266109, P.R. China
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5
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Lee S, Ha HP, Lee JH, Kim J. Uncovering the centrality of mono-dentate SO 32-/SO 42- modifiers grafted on a metal vanadate in accelerating wet NO X reduction and poison pyrolysis. JOURNAL OF HAZARDOUS MATERIALS 2023; 460:132278. [PMID: 37619273 DOI: 10.1016/j.jhazmat.2023.132278] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/16/2023] [Revised: 08/08/2023] [Accepted: 08/11/2023] [Indexed: 08/26/2023]
Abstract
NOX rarely binds with labile oxygens of catalytic solids, whose Lewis acidic (LA) species possess higher binding strengths with NH3 (ENH3) and H2O than Brönsted acidic counterparts (BA--H+; -OH), oftentimes leading to elevate energy barrier (EBARRIER) and weaken H2O tolerance, respectively. These limit NH3-assisted wet NOX reduction via Langmuir-Hinshelwood-type or Eley-Rideal (ER)-type model on LA species, while leaving ER-type analogue on BA--H+ species proper to reduce wet NOX. Given hard-to-regulate strength/amount of -OH species and occasional association between ENH3 and EBARRIER, Ni1V2O6 (Ni1) was rationally chosen as a platform to isolate mono-dentate SO32-/SO42- species for use as BA--H+ bonds via protonation to increase collision frequency (k'APP,0) alongside with disclosure of advantages of SO32-/SO42--functionalized Ni1V2O6 (Ni1-S) over Ni1 in reducing wet NOX. Ni1-S outperformed Ni1 in achieving a larger BA--H+ quantity (k'APP,0↑), increasing H2O tolerance, and elevating oxygen mobility, thus promoting NOX reduction activity/consequences under SO2-excluding gases. V2O5-WO3 composite simulating a commercial catalyst could isolate mono-dentate SO32-/SO42- species and served as a control (V2O5-WO3-S) for comparison. Ni1-S was superior to V2O5-WO3-S in evading ammonium (bi-)sulfate (AS/ABS) poison accumulation and expediting AS/ABS pyrolysis efficiency, thereby improving AS/ABS resistance under SO2-including gases, while enhancing resistance against hydro-thermal aging.
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Affiliation(s)
- Seokhyun Lee
- Extreme Materials Research Center, Korea Institute of Science and Technology, Seoul 02792, South Korea; Department of Chemical & Biological Engineering, Korea University, Seoul 02841, South Korea
| | - Heon Phil Ha
- Extreme Materials Research Center, Korea Institute of Science and Technology, Seoul 02792, South Korea
| | - Jung-Hyun Lee
- Department of Chemical & Biological Engineering, Korea University, Seoul 02841, South Korea
| | - Jongsik Kim
- Department of Chemical Engineering (Integrated Engineering Program), Kyung Hee University, Yongin 17104, South Korea.
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6
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Kim SI, Choi YJ, Lee MS, Lee DH. Nitration-Promoted Vanadate Catalysts for Low-Temperature Selective Catalytic Reduction of NO X with NH 3. ACS OMEGA 2023; 8:34152-34159. [PMID: 37744798 PMCID: PMC10515594 DOI: 10.1021/acsomega.3c05423] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 07/26/2023] [Accepted: 08/29/2023] [Indexed: 09/26/2023]
Abstract
Vanadium-based catalysts have been commercially used in selective catalytic reduction (SCR), owing to their high catalytic activity and effectiveness across a wide temperature range; however, their catalytic efficiency decreases at lower temperatures under exposure to SOX. This decrease is largely due to ammonium sulfate generation on the catalyst surface. To overcome this limitation, we added ammonium nitrate to the V2O5-WO3/TiO2 catalyst, producing a V2O5-WO3/TiO2 catalyst with nitrate functional groups. With this approach, we found that it was possible to adjust the amount of these functional groups by varying the amount of ammonium nitrate. Overall, the resultant nitrate V2O5-WO3/TiO2 catalyst has large quantities of NO3- and chemisorbed oxygen, which improves the density of Brønsted and Lewis acid sites on the catalyst surface. Furthermore, the nitrated V2O5-WO3/TiO2 catalyst has a high NOX removal efficiency and N2 selectivity at low temperatures (i.e., 300 °C); this is because NO3- and chemisorbed oxygen, generated by nitrate treatment, facilitated the occurrence of a fast SCR reaction. The approach outlined in this study can be applied to a wide range of SCR catalysts, allowing for the development of more, low-temperature SCR catalysts.
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Affiliation(s)
- Sun-I Kim
- Green
Materials and Processes R&D Group, Korea
Institute of Industrial Technology, Ulsan 44413, Republic of Korea
| | - Yeong Jun Choi
- Green
Materials and Processes R&D Group, Korea
Institute of Industrial Technology, Ulsan 44413, Republic of Korea
| | - Min Seong Lee
- Green
Materials and Processes R&D Group, Korea
Institute of Industrial Technology, Ulsan 44413, Republic of Korea
| | - Duck Hyun Lee
- Green
Materials and Processes R&D Group, Korea
Institute of Industrial Technology, Ulsan 44413, Republic of Korea
- School
of Advanced Materials & Electrical Engineering, Industrial Technology
Center for Environment-Friendly Materials, Andong National University, Andong 36729, Republic
of Korea
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7
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Fan Y, Zhang J, Yang L, Lu M, Ying T, Deng B, Dai W, Luo X, Zou J, Luo S. Enhancing SO2-shielding effect and Lewis acid sites for high efficiency in low-temperature SCR of NO with NH3: Reinforced electron-deficient extent of Fe3+ enabled by Ti4+ in Fe2O3. Sep Purif Technol 2023. [DOI: 10.1016/j.seppur.2023.123272] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023]
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8
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Elucidating the Sensitivity of Vanadyl Species to Water over V2O5/TiO2 Catalysts for NOx Abatement via Operando Raman Spectroscopy. J Catal 2022. [DOI: 10.1016/j.jcat.2022.11.003] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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9
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Zou J, Impeng S, Wang F, Lan T, Wang L, Wang P, Zhang D. Compensation or Aggravation: Pb and SO 2 Copoisoning Effects over Ceria-Based Catalysts for NO x Reduction. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2022; 56:13368-13378. [PMID: 36074097 DOI: 10.1021/acs.est.2c03653] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/15/2023]
Abstract
Severe catalyst deactivation caused by multiple poisons, including heavy metals and SO2, remains an obstinate issue for the selective catalytic reduction (SCR) of NOx by NH3. The copoisoning effects of heavy metals and SO2 are still unclear and irreconcilable. Herein, the unanticipated differential compensated or aggravated Pb and SO2 copoisoning effects over ceria-based catalysts for NOx reduction was originally unraveled. It was demonstrated that Pb and SO2 exhibited a compensated copoisoning effect over the CeO2/TiO2 (CT) catalyst with sole active CeO2 sites but an aggravated copoisoning effect over the CeO2-WO3/TiO2 (CWT) catalyst with dual active CeO2 sites and acidic WO3 sites. Furthermore, it was uniquely revealed that Pb preferred bonding with CeO2 among CT while further being combined with SO2 to form PbSO4 after copoisoning, which released the poisoned active CeO2 sites and rendered the copoisoned CT catalyst a recovered reactivity. In comparison, Pb and SO2 would poison acidic WO3 sites and active CeO2 sites, respectively, resulting in a seriously degraded reactivity of the copoisoned CWT catalyst. Therefore, this work thoroughly illustrates the internal mechanism of differential compensated or aggravated deactivation effects for Pb and SO2 copoisoning over CT and CWT catalysts and provides effective solutions to design ceria-based SCR catalysts with remarkable copoisoning resistance for the coexistence of heavy metals and SO2.
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Affiliation(s)
- Jingjing Zou
- International Joint Laboratory of Catalytic Chemistry, Department of Chemistry, Research Center of Nanoscience and Technology, College of Sciences, Shanghai University, Shanghai 200444, China
| | - Sarawoot Impeng
- National Nanotechnology Center, National Science and Technology Development Agency, Pathum Thani 12120, Thailand
| | - Fuli Wang
- International Joint Laboratory of Catalytic Chemistry, Department of Chemistry, Research Center of Nanoscience and Technology, College of Sciences, Shanghai University, Shanghai 200444, China
| | - Tianwei Lan
- International Joint Laboratory of Catalytic Chemistry, Department of Chemistry, Research Center of Nanoscience and Technology, College of Sciences, Shanghai University, Shanghai 200444, China
| | - Lulu Wang
- International Joint Laboratory of Catalytic Chemistry, Department of Chemistry, Research Center of Nanoscience and Technology, College of Sciences, Shanghai University, Shanghai 200444, China
| | - Penglu Wang
- International Joint Laboratory of Catalytic Chemistry, Department of Chemistry, Research Center of Nanoscience and Technology, College of Sciences, Shanghai University, Shanghai 200444, China
| | - Dengsong Zhang
- International Joint Laboratory of Catalytic Chemistry, Department of Chemistry, Research Center of Nanoscience and Technology, College of Sciences, Shanghai University, Shanghai 200444, China
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10
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Chen W, Yang S, Liu H, Huang F, Shao Q, Liu L, Sun J, Sun C, Chen D, Dong L. Single-Atom Ce-Modified α-Fe 2O 3 for Selective Catalytic Reduction of NO with NH 3. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2022; 56:10442-10453. [PMID: 35749227 DOI: 10.1021/acs.est.2c02916] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/15/2023]
Abstract
A single-atom Ce-modified α-Fe2O3 catalyst (Fe0.93Ce0.07Ox catalyst with 7% atomic percentage of Ce) was synthesized by a citric acid-assisted sol-gel method, which exhibited excellent performance for selective catalytic reduction of NOx with NH3 (NH3-SCR) over a wide operating temperature window. Remarkably, it maintained ∼93% NO conversion efficiency for 168 h in the presence of 200 ppm SO2 and 5 vol % H2O at 250 °C. The structural characterizations suggested that the introduction of Ce leads to the generation of local Fe-O-Ce sites in the FeOx matrix. Furthermore, it is critical to maintain the atomic dispersion of the Ce species to maximize the amounts of Fe-O-Ce sites in the Ce-doped FeOx catalyst. The formation of CeO2 nanoparticles due to a high doping amount of Ce species leads to a decline in catalytic performance, indicating a size-dependent catalytic behavior. Density functional theory (DFT) calculation results indicate that the formation of oxygen vacancies in the Fe-O-Ce sites is more favorable than that in the Fe-O-Fe sites in the Ce-free α-Fe2O3 catalyst. The Fe-O-Ce sites can promote the oxidation of NO to NO2 on the Fe0.93Ce0.07Ox catalyst and further facilitate the reduction of NOx by NH3. In addition, the decomposition of NH4HSO4 can occur at lower temperatures on the Fe0.93Ce0.07Ox catalyst containing atomically dispersed Ce species than on the α-Fe2O3 reference catalyst, resulting in the good SO2/H2O resistance ability in the NH3-SCR reaction.
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Affiliation(s)
- Wei Chen
- Shandong Provincial Key Laboratory of Clean Production of Fine Chemicals, College of Chemistry, Chemical Engineering and Materials Science, Institute of Materials and Clean Energy, Shandong Normal University, Jinan 250014, P. R. China
| | - Shan Yang
- Shandong Provincial Key Laboratory of Clean Production of Fine Chemicals, College of Chemistry, Chemical Engineering and Materials Science, Institute of Materials and Clean Energy, Shandong Normal University, Jinan 250014, P. R. China
| | - Hao Liu
- Shandong Provincial Key Laboratory of Clean Production of Fine Chemicals, College of Chemistry, Chemical Engineering and Materials Science, Institute of Materials and Clean Energy, Shandong Normal University, Jinan 250014, P. R. China
| | - Fang Huang
- Shandong Provincial Key Laboratory of Clean Production of Fine Chemicals, College of Chemistry, Chemical Engineering and Materials Science, Institute of Materials and Clean Energy, Shandong Normal University, Jinan 250014, P. R. China
| | - Qinghao Shao
- Shandong Provincial Key Laboratory of Clean Production of Fine Chemicals, College of Chemistry, Chemical Engineering and Materials Science, Institute of Materials and Clean Energy, Shandong Normal University, Jinan 250014, P. R. China
| | - Lichen Liu
- Department of Chemistry, Tsinghua University, Beijing 100084, P. R. China
| | - Jingfang Sun
- Jiangsu Key Laboratory of Vehicle Emissions Control, School of the Environment, Nanjing University, Nanjing 210093, P. R. China
| | - Chuanzhi Sun
- Shandong Provincial Key Laboratory of Clean Production of Fine Chemicals, College of Chemistry, Chemical Engineering and Materials Science, Institute of Materials and Clean Energy, Shandong Normal University, Jinan 250014, P. R. China
| | - Dezhan Chen
- Shandong Provincial Key Laboratory of Clean Production of Fine Chemicals, College of Chemistry, Chemical Engineering and Materials Science, Institute of Materials and Clean Energy, Shandong Normal University, Jinan 250014, P. R. China
| | - Lin Dong
- Jiangsu Key Laboratory of Vehicle Emissions Control, School of the Environment, Nanjing University, Nanjing 210093, P. R. China
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11
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Chen Y, Zhang Y, Feng X, Li J, Liu W, Ren S, Yang J, Liu Q. In situ deposition of 0D CeO 2 quantum dots on Fe 2O 3-containing solid waste NH 3-SCR catalyst: Enhancing redox and NH 3 adsorption ability. WASTE MANAGEMENT (NEW YORK, N.Y.) 2022; 149:323-332. [PMID: 35772293 DOI: 10.1016/j.wasman.2022.06.030] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/08/2022] [Revised: 06/13/2022] [Accepted: 06/21/2022] [Indexed: 06/15/2023]
Abstract
As NOx has been turning into a crucial environmental problem, NH3-SCR technology with relatively simple device, reliable operation and low secondary pollution, has become a widely used commercial and mature de-nitration technology. However, some weaknesses restricted the further application of commercialized V2O5-WO3/TiO2 NH3-SCR catalysts, while Fe2O3-based catalysts have received much attention due to their high thermal stability, passable N2 selectivity and low cost. In this study, Fe2O3-containing solid waste derived from Zn extraction process of electric arc furnace dust was exploited as the base material for catalyst preparing. Owing to the complementary and synergistic effect of CeO2 and Fe2O3, 0D CeO2 quantum dots (CeQDs) with fully-exposed active sites, large specific surface area, and rapid charge transfer have been introduced and deposited onto Fe2O3-containing solid waste nanorods. The in-situ deposition of CeQDs led to the admirable enhancement in NH3-SCR catalytic activity, N2 selectivity and SO2 tolerance of the extremely low-cost Fe2O3 catalyst. Comprehensive characterizations and DFT calculations describing the adsorption of O2 and NH3 were applied to analyze the catalyst structure and further investigate the detailed relationship between structural properties and activity as well as reaction mechanism. This work provides new insights for the high-value utilization of iron-containing solid waste and a practical reference for boosting the performance of NH3-SCR catalysts by introducing quantum dots.
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Affiliation(s)
- Yangfan Chen
- College of Materials Science and Engineering, Chongqing University, Chongqing 400044, PR China
| | - Yuchen Zhang
- College of Materials Science and Engineering, Chongqing University, Chongqing 400044, PR China
| | - Xin Feng
- College of Materials Science and Engineering, Chongqing University, Chongqing 400044, PR China
| | - Jiangling Li
- College of Materials Science and Engineering, Chongqing University, Chongqing 400044, PR China; Chongqing Key Laboratory of Vanadium-Titanium Metallurgical and New Materials, Chongqing University, Chongqing 400044, PR China.
| | - Weizao Liu
- College of Materials Science and Engineering, Chongqing University, Chongqing 400044, PR China; Chongqing Key Laboratory of Vanadium-Titanium Metallurgical and New Materials, Chongqing University, Chongqing 400044, PR China
| | - Shan Ren
- College of Materials Science and Engineering, Chongqing University, Chongqing 400044, PR China; Chongqing Key Laboratory of Vanadium-Titanium Metallurgical and New Materials, Chongqing University, Chongqing 400044, PR China
| | - Jian Yang
- College of Materials Science and Engineering, Chongqing University, Chongqing 400044, PR China; Chongqing Key Laboratory of Vanadium-Titanium Metallurgical and New Materials, Chongqing University, Chongqing 400044, PR China
| | - Qingcai Liu
- College of Materials Science and Engineering, Chongqing University, Chongqing 400044, PR China; Chongqing Key Laboratory of Vanadium-Titanium Metallurgical and New Materials, Chongqing University, Chongqing 400044, PR China
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