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Li S, Zhang B, Yang Y, Zhu F, Zhao D, Shi S, Wang S, Ding S, Chen C. Insights into the Acidic Site in Manganese Oxide in Terms of the Sulfur and Water Tolerance of Low-Temperature NH 3 Selective Catalytic Reduction. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2024; 40:14504-14514. [PMID: 38951117 DOI: 10.1021/acs.langmuir.4c01289] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 07/03/2024]
Abstract
A critical constraint impeding the utilization of Mn-based oxide catalysts in NH3 selective catalytic reduction (NH3-SCR) is their inadequate resistance to water and sulfur. This vulnerability primarily arises from the propensity of SO2 to bind to the acidic site in manganese oxide, resulting in the formation of metal sulfate and leading to the irreversible deactivation of the catalyst. Therefore, gaining a comprehensive understanding of the detrimental impact of SO2 on the acidic sites and elucidating the underlying mechanism of this toxicity are of paramount importance for the effective application of Mn-based catalysts in NH3-SCR. Herein, we strategically modulate the acidity of the manganese oxide catalyst surface through the incorporation of Ce and Nb. Comprehensive analyses, including thermogravimetry, NH3 temperature-programmed desorption, in situ diffused reflectance infrared Fourier transform spectroscopy, and density functional theory calculations, reveal that SO2 exhibits a propensity for adsorption at strongly acidic sites. This mechanistic understanding underscores the pivotal role of surface acidity in governing the sulfur resistance of manganese oxide.
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Affiliation(s)
- Shengchen Li
- Key Laboratory of Jiangxi Province for Environment and Energy, School of Chemistry and Chemical Engineering, Nanchang University, Nanchang, Jiangxi 330031, P. R. China
| | - Bingzhen Zhang
- Key Laboratory of Jiangxi Province for Environment and Energy, School of Chemistry and Chemical Engineering, Nanchang University, Nanchang, Jiangxi 330031, P. R. China
| | - Yanping Yang
- Key Laboratory of Jiangxi Province for Environment and Energy, School of Chemistry and Chemical Engineering, Nanchang University, Nanchang, Jiangxi 330031, P. R. China
| | - Fangyu Zhu
- Key Laboratory of Jiangxi Province for Environment and Energy, School of Chemistry and Chemical Engineering, Nanchang University, Nanchang, Jiangxi 330031, P. R. China
| | - Dan Zhao
- Key Laboratory of Jiangxi Province for Environment and Energy, School of Chemistry and Chemical Engineering, Nanchang University, Nanchang, Jiangxi 330031, P. R. China
| | - Shunli Shi
- Key Laboratory of Jiangxi Province for Environment and Energy, School of Chemistry and Chemical Engineering, Nanchang University, Nanchang, Jiangxi 330031, P. R. China
| | - Shuhua Wang
- Key Laboratory of Jiangxi Province for Environment and Energy, School of Chemistry and Chemical Engineering, Nanchang University, Nanchang, Jiangxi 330031, P. R. China
| | - Shunmin Ding
- Key Laboratory of Jiangxi Province for Environment and Energy, School of Chemistry and Chemical Engineering, Nanchang University, Nanchang, Jiangxi 330031, P. R. China
| | - Chao Chen
- Key Laboratory of Jiangxi Province for Environment and Energy, School of Chemistry and Chemical Engineering, Nanchang University, Nanchang, Jiangxi 330031, P. R. China
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Xing L, Chen Z, Zhan G, Huang Z, Li M, Li Y, Wang L, Li J. Sulfur Migration Enhanced Proton-Coupled Electron Transfer for Efficient CO 2 Desorption with Core-Shelled C@Mn 3O 4. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2024; 58:4606-4616. [PMID: 38427797 DOI: 10.1021/acs.est.3c09875] [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: 03/03/2024]
Abstract
Transforming hazardous species into active sites by ingenious material design was a promising and positive strategy to improve catalytic reactions in industrial applications. To synergistically address the issue of sluggish CO2 desorption kinetics and SO2-poisoning solvent of amine scrubbing, we propose a novel method for preparing a high-performance core-shell C@Mn3O4 catalyst for heterogeneous sulfur migration and in situ reconstruction to active -SO3H groups, and thus inducing an enhanced proton-coupled electron transfer (PCET) effect for CO2 desorption. As anticipated, the rate of CO2 desorption increases significantly, by 255%, when SO2 is introduced. On a bench scale, dynamic CO2 capture experiments reveal that the catalytic regeneration heat duty of SO2-poisoned solvent experiences a 32% reduction compared to the blank case, while the durability of the catalyst is confirmed. Thus, the enhanced PCET of C@Mn3O4, facilitated by sulfur migration and simultaneous transformation, effectively improves the SO2 resistance and regeneration efficiency of amine solvents, providing a novel route for pursuing cost-effective CO2 capture with an amine solvent.
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Affiliation(s)
- Lei Xing
- State Key Joint Laboratory of Environment Simulation and Pollution Control, School of Environment, Tsinghua University, Beijing 100084, PR China
- MOE Key Laboratory of Resources and Environmental Systems Optimization, College of Environmental Science and Engineering, North China Electric Power University, Beijing 102206, PR China
| | - Zhen Chen
- State Key Joint Laboratory of Environment Simulation and Pollution Control, School of Environment, Tsinghua University, Beijing 100084, PR China
| | - Guoxiong Zhan
- State Key Joint Laboratory of Environment Simulation and Pollution Control, School of Environment, Tsinghua University, Beijing 100084, PR China
| | - Zhoulan Huang
- State Key Joint Laboratory of Environment Simulation and Pollution Control, School of Environment, Tsinghua University, Beijing 100084, PR China
| | - Mingyue Li
- MOE Key Laboratory of Resources and Environmental Systems Optimization, College of Environmental Science and Engineering, North China Electric Power University, Beijing 102206, PR China
| | - Yuchen Li
- MOE Key Laboratory of Resources and Environmental Systems Optimization, College of Environmental Science and Engineering, North China Electric Power University, Beijing 102206, PR China
| | - Lidong Wang
- MOE Key Laboratory of Resources and Environmental Systems Optimization, College of Environmental Science and Engineering, North China Electric Power University, Beijing 102206, PR China
| | - Junhua Li
- State Key Joint Laboratory of Environment Simulation and Pollution Control, School of Environment, Tsinghua University, Beijing 100084, PR China
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Wijerathne A, Sawyer A, Daya R, Paolucci C. Competition between Mononuclear and Binuclear Copper Sites across Different Zeolite Topologies. JACS AU 2024; 4:197-215. [PMID: 38274255 PMCID: PMC10806779 DOI: 10.1021/jacsau.3c00632] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 10/18/2023] [Revised: 12/12/2023] [Accepted: 12/20/2023] [Indexed: 01/27/2024]
Abstract
A key challenge for metal-exchanged zeolites is the determination of metal cation speciation and nuclearity under synthesis and reaction conditions. Copper-exchanged zeolites, which are widely used in automotive emissions control and potential catalysts for partial methane oxidation, have in particular evidenced a wide variety of Cu structures that are observed to change with exposure conditions, zeolite composition, and topology. Here, we develop predictive models for Cu cation speciation and nuclearity in CHA, MOR, BEA, AFX, and FER zeolite topologies using interatomic potentials, quantum chemical calculations, and Monte Carlo simulations to interrogate this vast configurational and compositional space. Model predictions are used to rationalize experimentally observed differences between Cu-zeolites in a wide-body of literature, including nuclearity populations, structural variations, and methanol per Cu yields. Our results show that both topological features and commonly observed Al-siting biases in MOR zeolites increase the population of binuclear Cu sites, explaining the small population of mononuclear Cu sites observed in these materials relative to other zeolites such as CHA and BEA. Finally, we used a machine learning classification model to determine the preference to form mononuclear or binuclear Cu sites at different Al configurations in 200 zeolites in the international zeolite database. Model results reveal several zeolite topologies at extreme ends of the mononuclear vs binuclear spectrum, highlighting synthetic options for realization of zeolites with strong Cu nuclearity preferences.
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Affiliation(s)
- Asanka Wijerathne
- Department
of Chemical Engineering, University of Virginia, Charlottesville, Virginia 22903, United States
| | - Allison Sawyer
- Department
of Chemical Engineering, University of Virginia, Charlottesville, Virginia 22903, United States
| | - Rohil Daya
- Cummins
Inc, Columbus, Indiana 47201, United States
| | - Christopher Paolucci
- Department
of Chemical Engineering, University of Virginia, Charlottesville, Virginia 22903, United States
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Molokova AY, Abasabadi RK, Borfecchia E, Mathon O, Bordiga S, Wen F, Berlier G, Janssens TVW, Lomachenko KA. Elucidating the reaction mechanism of SO 2 with Cu-CHA catalysts for NH 3-SCR by X-ray absorption spectroscopy. Chem Sci 2023; 14:11521-11531. [PMID: 37886093 PMCID: PMC10599480 DOI: 10.1039/d3sc03924b] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/2023] [Accepted: 10/02/2023] [Indexed: 10/28/2023] Open
Abstract
The application of Cu-CHA catalysts for the selective catalytic reduction of NOx by ammonia (NH3-SCR) in exhaust systems of diesel vehicles requires the use of fuel with low sulfur content, because the Cu-CHA catalysts are poisoned by higher concentrations of SO2. Understanding the mechanism of the interaction between the Cu-CHA catalyst and SO2 is crucial for elucidating the SO2 poisoning and development of efficient catalysts for SCR reactions. Earlier we have shown that SO2 reacts with the [Cu2II(NH3)4O2]2+ complex that is formed in the pores of Cu-CHA upon activation of O2 in the NH3-SCR cycle. In order to determine the products of this reaction, we use X-ray absorption spectroscopy (XAS) at the Cu K-edge and S K-edge, and X-ray emission spectroscopy (XES) for Cu-CHA catalysts with 0.8 wt% Cu and 3.2 wt% Cu loadings. We find that the mechanism for SO2 uptake is similar for catalysts with low and high Cu content. We show that the SO2 uptake proceeds via an oxidation of SO2 by the [Cu2II(NH3)4O2]2+ complex, resulting in the formation of different CuI species, which do not react with SO2, and a sulfated CuII complex that is accumulated in the pores of the zeolite. The increase of the SO2 uptake upon addition of oxygen to the SO2-containing feed, evidenced by X-ray adsorbate quantification (XAQ) and temperature-programmed desorption of SO2, is explained by the re-oxidation of the CuI species into the [Cu2II(NH3)4O2]2+ complexes, which makes them available for reaction with SO2.
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Affiliation(s)
- Anastasia Yu Molokova
- European Synchrotron Radiation Facility 71 avenue des Martyrs CS 40220 38043 Grenoble Cedex 9 France
- Department of Chemistry and NIS Centre, University of Turin via Giuria 7 10125 Turin Italy
| | - Reza K Abasabadi
- Department of Chemistry and NIS Centre, University of Turin via Giuria 7 10125 Turin Italy
- Umicore Denmark ApS Kogle Allé 1 2970 Hørsholm Denmark
| | - Elisa Borfecchia
- Department of Chemistry and NIS Centre, University of Turin via Giuria 7 10125 Turin Italy
| | - Olivier Mathon
- European Synchrotron Radiation Facility 71 avenue des Martyrs CS 40220 38043 Grenoble Cedex 9 France
| | - Silvia Bordiga
- Department of Chemistry and NIS Centre, University of Turin via Giuria 7 10125 Turin Italy
| | - Fei Wen
- Umicore AG & Co Rodenbacher Chaussee 4 63457 Hanau Germany
| | - Gloria Berlier
- Department of Chemistry and NIS Centre, University of Turin via Giuria 7 10125 Turin Italy
| | | | - Kirill A Lomachenko
- European Synchrotron Radiation Facility 71 avenue des Martyrs CS 40220 38043 Grenoble Cedex 9 France
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Cao X, Zhang Q, Yang W, Fang L, Liu S, Ma R, Guo K, Ma N. Lead-chlorine synergistic immobilization mechanism in municipal solid waste incineration fly ash (MSWIFA)-based magnesium potassium phosphate cement. JOURNAL OF HAZARDOUS MATERIALS 2023; 442:130038. [PMID: 36166907 DOI: 10.1016/j.jhazmat.2022.130038] [Citation(s) in RCA: 10] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/20/2022] [Revised: 09/05/2022] [Accepted: 09/18/2022] [Indexed: 06/16/2023]
Abstract
The high chlorine (Cl) and lead (Pb) content characteristics of municipal solid waste incineration fly ash (MSWIFA) pose environmental risks and hinder resource utilization. Herein, an MSWIFA-based magnesium potassium phosphate cement (MKPC) preparation strategy was developed, which allowed the MSWIFA recycling and the Pb-Cl synergistic immobilization without the washing pretreatment. The compressive strength of the resulting 10 wt% MSWIFA-based MKPC was 28.44 MPa, with over 99.2% reduction in leaching toxicity of Pb and Cl. The high-angle annular dark field scanning transmission electron microscope (HAADF-STEM) and X-ray absorption spectroscopy (XAS) analyzes showed that Pb, phosphate and Cl- formed Pb5(PO4)3Cl in MKPC. In-situ X-ray diffraction (XRD) tests showed that Pb3(PO4)2 was gradually transformed to Pb5(PO4)3Cl through a dissolution-precipitation process. The formation energy, Bader charge, charge density difference and density of states (DOS) of Pb5(PO4)3Cl were analyzed by first-principles calculations, confirming that Pb5(PO4)3Cl was more thermodynamically stable than Pb3(PO4)2 and PbCl2 and that electronic interactions between Pb-p, O-p, P-p and Cl-p orbits were the origin of Pb-Cl synergistic immobilization. This work provides a new strategy for the resource utilization of MSWIFA without washing pretreatment, and provides an in-depth understanding of the Pb-Cl synergistic immobilization mechanism.
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Affiliation(s)
- Xing Cao
- College of Chemistry and Environmental Engineering, Shenzhen University, Shenzhen 518060, China
| | - Qiushi Zhang
- College of Chemistry and Environmental Engineering, Shenzhen University, Shenzhen 518060, China
| | - Weichen Yang
- College of Chemistry and Environmental Engineering, Shenzhen University, Shenzhen 518060, China
| | - Lin Fang
- College of Chemistry and Environmental Engineering, Shenzhen University, Shenzhen 518060, China
| | - Shiwei Liu
- College of Chemistry and Environmental Engineering, Shenzhen University, Shenzhen 518060, China
| | - Rui Ma
- College of Chemistry and Environmental Engineering, Shenzhen University, Shenzhen 518060, China.
| | - Kai Guo
- College of Chemistry and Environmental Engineering, Shenzhen University, Shenzhen 518060, China
| | - Ning Ma
- China Electronic System Engineering Co.,Ltd, Beijing 100040, China
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Mechanism for SO Poisoning of Cu-CHA during Low Temperature NH-SCR. J Catal 2022. [DOI: 10.1016/j.jcat.2022.12.023] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
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Research Progress on Sulfur Deactivation and Regeneration over Cu-CHA Zeolite Catalyst. Catalysts 2022. [DOI: 10.3390/catal12121499] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
Abstract
Benefiting from the exceptional selective catalytic reduction of NOx with ammonia (NH3-SCR) activity, excellent N2 selectivity, and superior hydrothermal durability, the Cu2+-exchanged zeolite catalyst with a chabazite structure (Cu-CHA) has been considered the predominant SCR catalyst in nitrogen oxide (NOx) abatement. However, sulfur poisoning remains one of the most significant deterrents to the catalyst in real applications. This review summarizes the NH3-SCR reaction mechanism on Cu-CHA, including the active sites and the nature of hydrothermal aging resistance. On the basis of the NH3-SCR reaction mechanism, the review gives a comprehensive summary of sulfate species, sulfate loading, emitted gaseous composition, and the impact of exposure temperature/time on Cu-CHA. The nature of the regeneration of sulfated catalysts is also covered in this review. The review gives a valuable summary of new insights into the matching between the design of NH3-SCR activity and sulfur resistance, highlighting the opportunities and challenges presented by Cu-CHA. Guidance for future sulfur poisoning diagnosis, effective regeneration strategies, and a design for an efficient catalyst for the aftertreatment system (ATS) are proposed to minimize the deterioration of NOx abatement in the future. Finally, we call for more attention to be paid to the effects of PO43- and metal co-cations with sulfur in the ATS.
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