Mobility and Reactivity of Cu+ Species in Cu-CHA Catalysts under NH3-SCR-NOx Reaction Conditions: Insights from AIMD Simulations

The mobility of the copper cations acting as active sites for the selective catalytic reduction of nitrogen oxides with ammonia in Cu-CHA catalysts varies with temperature and feed composition. Herein, the migration of [Cu(NH3)2]+ complexes between two adjacent cavities of the chabazite structure, i...

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Autores: Millán, Reisel, Cnudde, Pieter, van Speybroeck, Veronique, Boronat, Mercedes
Tipo de recurso: artículo
Estado:Versión publicada
Fecha de publicación:2021
País:España
Institución:Consejo Superior de Investigaciones Científicas (CSIC)
Repositorio:DIGITAL.CSIC. Repositorio Institucional del CSIC
OAI Identifier:oai:digital.csic.es:10261/271337
Acceso en línea:http://hdl.handle.net/10261/271337
Access Level:acceso abierto
Palabra clave:Zeolite
Molecular dynamics
Cation mobility
DFT
Mechanism
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spelling Mobility and Reactivity of Cu+ Species in Cu-CHA Catalysts under NH3-SCR-NOx Reaction Conditions: Insights from AIMD SimulationsMillán, ReiselCnudde, Pietervan Speybroeck, VeroniqueBoronat, MercedesZeoliteMolecular dynamicsCation mobilityDFTMechanismThe mobility of the copper cations acting as active sites for the selective catalytic reduction of nitrogen oxides with ammonia in Cu-CHA catalysts varies with temperature and feed composition. Herein, the migration of [Cu(NH3)2]+ complexes between two adjacent cavities of the chabazite structure, including other reactant molecules (NO, O2, H2O, and NH3), in the initial and final cavities is investigated using ab initio molecular dynamics (AIMD) simulations combined with enhanced sampling techniques to describe hopping events from one cage to the other. We find that such diffusion is only significantly hindered by the presence of excess NH3 or NO in the initial cavity, since both reactants form with [Cu(NH3)2]+ stable intermediates which are too bulky to cross the 8-ring windows connecting the cavities. The presence of O2 modifies strongly the interaction of NO with Cu+. At low temperatures, we observe NO detachment from Cu+ and increased mobility of the [Cu(NH3)2]+ complex, while at high temperatures, NO reacts spontaneously with O2 to form NO2. The present simulations give evidence for recent experimental observations, namely, an NH3 inhibition effect on the SCR reaction at low temperatures, and transport limitations of NO and NH3 at high temperatures. Our first principle simulations mimicking operating conditions support the existence of two different reaction mechanisms operating at low and high temperatures, the former involving dimeric Cu(NH3)2-O2-Cu(NH3)2 species and the latter occurring by direct NO oxidation to NO2 in one single cavity.This work has been supported by the Spanish Government through Severo Ochoa (SEV-2016-0683, MINECO), and MAT2017-82288-C2-1-P (AEI/FEDER, UE) projects, and by CSIC through the i-link+ program (LINKA20381). We thankfully acknowledge Red Española de Supercomputación (RES) and Servei d’Informàtica de la Universitat de València (SIUV) for computational resources and technical support, the computer resources at Marenostrum4 (RES-QS-2020-1-0029 and RES-QS.2020-2-0015) and the technical support provided by BSC. R.M. thanks ITQ for his contract. V.V.S, P.C. acknowledge funding from the European Union’s Horizon 2020 research and innovation program (consolidator ERC grant agreement No. 647755 - DYNPOR (2015-2020)). V.V.S. acknowledges the Research Board of the Ghent University (BOF). Part of the computational resources and services used were provided by Ghent University (Stevin Supercomputer Infrastructure), the VSC (Flemish Supercomputer Center), funded by the Research Foundation - Flanders (FWO).Peer reviewedACS PublicationsMinisterio de Economía y Competitividad (España)European CommissionConsejo Superior de Investigaciones Científicas [https://ror.org/02gfc7t72]202220222021info:eu-repo/semantics/articlehttp://purl.org/coar/resource_type/c_6501Publisher's versioninfo:eu-repo/semantics/publishedVersionhttp://hdl.handle.net/10261/271337reponame:DIGITAL.CSIC. Repositorio Institucional del CSICinstname:Consejo Superior de Investigaciones Científicas (CSIC)Inglés#PLACEHOLDER_PARENT_METADATA_VALUE##PLACEHOLDER_PARENT_METADATA_VALUE##PLACEHOLDER_PARENT_METADATA_VALUE#info:eu-repo/grantAgreement/AEI/Plan Estatal de Investigación Científica y Técnica y de Innovación 2013-2016/MAT2017-82288-C2-1-Pinfo:eu-repo/grantAgraament/MINECO/Plan Estatal de Investigación Científica y Técnica y de Innovación 2013-2016/SEV-2016-0683info:eu-repo/grantAgreement/EC/Horizon 2020/. The Framework Programme for Research and Innovationhttps://pubs.acs.org/doi/10.1021/jacsau.1c00337Síinfo:eu-repo/semantics/openAccessoai:digital.csic.es:10261/2713372026-05-22T06:33:51Z
dc.title.none.fl_str_mv Mobility and Reactivity of Cu+ Species in Cu-CHA Catalysts under NH3-SCR-NOx Reaction Conditions: Insights from AIMD Simulations
title Mobility and Reactivity of Cu+ Species in Cu-CHA Catalysts under NH3-SCR-NOx Reaction Conditions: Insights from AIMD Simulations
spellingShingle Mobility and Reactivity of Cu+ Species in Cu-CHA Catalysts under NH3-SCR-NOx Reaction Conditions: Insights from AIMD Simulations
Millán, Reisel
Zeolite
Molecular dynamics
Cation mobility
DFT
Mechanism
title_short Mobility and Reactivity of Cu+ Species in Cu-CHA Catalysts under NH3-SCR-NOx Reaction Conditions: Insights from AIMD Simulations
title_full Mobility and Reactivity of Cu+ Species in Cu-CHA Catalysts under NH3-SCR-NOx Reaction Conditions: Insights from AIMD Simulations
title_fullStr Mobility and Reactivity of Cu+ Species in Cu-CHA Catalysts under NH3-SCR-NOx Reaction Conditions: Insights from AIMD Simulations
title_full_unstemmed Mobility and Reactivity of Cu+ Species in Cu-CHA Catalysts under NH3-SCR-NOx Reaction Conditions: Insights from AIMD Simulations
title_sort Mobility and Reactivity of Cu+ Species in Cu-CHA Catalysts under NH3-SCR-NOx Reaction Conditions: Insights from AIMD Simulations
dc.creator.none.fl_str_mv Millán, Reisel
Cnudde, Pieter
van Speybroeck, Veronique
Boronat, Mercedes
author Millán, Reisel
author_facet Millán, Reisel
Cnudde, Pieter
van Speybroeck, Veronique
Boronat, Mercedes
author_role author
author2 Cnudde, Pieter
van Speybroeck, Veronique
Boronat, Mercedes
author2_role author
author
author
dc.contributor.none.fl_str_mv Ministerio de Economía y Competitividad (España)
European Commission
Consejo Superior de Investigaciones Científicas [https://ror.org/02gfc7t72]
dc.subject.none.fl_str_mv Zeolite
Molecular dynamics
Cation mobility
DFT
Mechanism
topic Zeolite
Molecular dynamics
Cation mobility
DFT
Mechanism
description The mobility of the copper cations acting as active sites for the selective catalytic reduction of nitrogen oxides with ammonia in Cu-CHA catalysts varies with temperature and feed composition. Herein, the migration of [Cu(NH3)2]+ complexes between two adjacent cavities of the chabazite structure, including other reactant molecules (NO, O2, H2O, and NH3), in the initial and final cavities is investigated using ab initio molecular dynamics (AIMD) simulations combined with enhanced sampling techniques to describe hopping events from one cage to the other. We find that such diffusion is only significantly hindered by the presence of excess NH3 or NO in the initial cavity, since both reactants form with [Cu(NH3)2]+ stable intermediates which are too bulky to cross the 8-ring windows connecting the cavities. The presence of O2 modifies strongly the interaction of NO with Cu+. At low temperatures, we observe NO detachment from Cu+ and increased mobility of the [Cu(NH3)2]+ complex, while at high temperatures, NO reacts spontaneously with O2 to form NO2. The present simulations give evidence for recent experimental observations, namely, an NH3 inhibition effect on the SCR reaction at low temperatures, and transport limitations of NO and NH3 at high temperatures. Our first principle simulations mimicking operating conditions support the existence of two different reaction mechanisms operating at low and high temperatures, the former involving dimeric Cu(NH3)2-O2-Cu(NH3)2 species and the latter occurring by direct NO oxidation to NO2 in one single cavity.
publishDate 2021
dc.date.none.fl_str_mv 2021
2022
2022
dc.type.none.fl_str_mv info:eu-repo/semantics/article
http://purl.org/coar/resource_type/c_6501
Publisher's version
info:eu-repo/semantics/publishedVersion
format article
status_str publishedVersion
dc.identifier.none.fl_str_mv http://hdl.handle.net/10261/271337
url http://hdl.handle.net/10261/271337
dc.language.none.fl_str_mv Inglés
language_invalid_str_mv Inglés
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#PLACEHOLDER_PARENT_METADATA_VALUE#
#PLACEHOLDER_PARENT_METADATA_VALUE#
info:eu-repo/grantAgreement/AEI/Plan Estatal de Investigación Científica y Técnica y de Innovación 2013-2016/MAT2017-82288-C2-1-P
info:eu-repo/grantAgraament/MINECO/Plan Estatal de Investigación Científica y Técnica y de Innovación 2013-2016/SEV-2016-0683
info:eu-repo/grantAgreement/EC/Horizon 2020/. The Framework Programme for Research and Innovation
https://pubs.acs.org/doi/10.1021/jacsau.1c00337
Sí
dc.rights.none.fl_str_mv info:eu-repo/semantics/openAccess
eu_rights_str_mv openAccess
dc.publisher.none.fl_str_mv ACS Publications
publisher.none.fl_str_mv ACS Publications
dc.source.none.fl_str_mv reponame:DIGITAL.CSIC. Repositorio Institucional del CSIC
instname:Consejo Superior de Investigaciones Científicas (CSIC)
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