Critical effect of carbon vacancies on the reverse water gas shift reaction over vanadium carbide catalysts

Experimental and theoretical evidences show that carbon vacancies determine the catalytic behavior of vanadium carbides in the CO2 conversion to CO via the Reverse Water Gas Shift (RWGS) reaction. Two VCx samples, one mostly containing stoichiometric VC and the other being C deficient, mainly V8C7,...

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Autores: Pajares, Arturo, Prats Garcia, Hèctor, Romero, Alexandre, Viñes Solana, Francesc, Ramírez de la Piscina, Pilar, Sayós Ortega, Ramón, Homs Martí, Narcís, Illas i Riera, Francesc
Tipo de recurso: artículo
Estado:Versión aceptada para publicación
Fecha de publicación:2020
País:España
Institución:Universidad de Barcelona
Repositorio:Dipòsit Digital de la UB
OAI Identifier:oai:diposit.ub.edu:2445/165779
Acceso en línea:https://hdl.handle.net/2445/165779
Access Level:acceso abierto
Palabra clave:Teoria del funcional de densitat
Catàlisi heterogènia
Carburs
Density functionals
Heterogeneus catalysis
Carbides
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spelling Critical effect of carbon vacancies on the reverse water gas shift reaction over vanadium carbide catalystsPajares, ArturoPrats Garcia, HèctorRomero, AlexandreViñes Solana, FrancescRamírez de la Piscina, PilarSayós Ortega, RamónHoms Martí, NarcísIllas i Riera, FrancescTeoria del funcional de densitatCatàlisi heterogèniaCarbursDensity functionalsHeterogeneus catalysisCarbidesExperimental and theoretical evidences show that carbon vacancies determine the catalytic behavior of vanadium carbides in the CO2 conversion to CO via the Reverse Water Gas Shift (RWGS) reaction. Two VCx samples, one mostly containing stoichiometric VC and the other being C deficient, mainly V8C7, were synthesized, characterized, and studied. The samples show different CO2 adsorption heats, which correlate with those calculated using Density Functional Theory (DFT) on suitable models. The sample containing more V8C7 shows a higher CO2 conversion and CO selectivity and a lower apparent activation energy, being a stable catalyst over long-time tests. DFT calculations confirm that C vacancies in V8C7 are responsible for the observed catalytic behavior, allowing reactants to adsorb more strongly and lowering the energy barrier for both H2 and CO2 dissociation steps. The present work highlights the importance of such native point defects in the transition metal carbides surface chemistry and catalytic propertiesElsevier B.V.2020info:eu-repo/semantics/articleinfo:eu-repo/semantics/acceptedVersionapplication/pdfhttps://hdl.handle.net/2445/165779Articles publicats en revistes (Ciència dels Materials i Química Física)reponame:Dipòsit Digital de la UBinstname:Universidad de BarcelonaInglésVersió postprint del document publicat a: https://doi.org/10.1016/j.apcatb.2020.118719Applied Catalysis B-Environmental, 2020, vol. 267, p. 118719 -1-118719-10https://doi.org/10.1016/j.apcatb.2020.118719cc-by-nc-nd (c) Elsevier B.V., 2020http://creativecommons.org/licenses/by-nc-nd/3.0/esinfo:eu-repo/semantics/openAccessoai:diposit.ub.edu:2445/1657792026-05-27T06:46:51Z
dc.title.none.fl_str_mv Critical effect of carbon vacancies on the reverse water gas shift reaction over vanadium carbide catalysts
title Critical effect of carbon vacancies on the reverse water gas shift reaction over vanadium carbide catalysts
spellingShingle Critical effect of carbon vacancies on the reverse water gas shift reaction over vanadium carbide catalysts
Pajares, Arturo
Teoria del funcional de densitat
Catàlisi heterogènia
Carburs
Density functionals
Heterogeneus catalysis
Carbides
title_short Critical effect of carbon vacancies on the reverse water gas shift reaction over vanadium carbide catalysts
title_full Critical effect of carbon vacancies on the reverse water gas shift reaction over vanadium carbide catalysts
title_fullStr Critical effect of carbon vacancies on the reverse water gas shift reaction over vanadium carbide catalysts
title_full_unstemmed Critical effect of carbon vacancies on the reverse water gas shift reaction over vanadium carbide catalysts
title_sort Critical effect of carbon vacancies on the reverse water gas shift reaction over vanadium carbide catalysts
dc.creator.none.fl_str_mv Pajares, Arturo
Prats Garcia, Hèctor
Romero, Alexandre
Viñes Solana, Francesc
Ramírez de la Piscina, Pilar
Sayós Ortega, Ramón
Homs Martí, Narcís
Illas i Riera, Francesc
author Pajares, Arturo
author_facet Pajares, Arturo
Prats Garcia, Hèctor
Romero, Alexandre
Viñes Solana, Francesc
Ramírez de la Piscina, Pilar
Sayós Ortega, Ramón
Homs Martí, Narcís
Illas i Riera, Francesc
author_role author
author2 Prats Garcia, Hèctor
Romero, Alexandre
Viñes Solana, Francesc
Ramírez de la Piscina, Pilar
Sayós Ortega, Ramón
Homs Martí, Narcís
Illas i Riera, Francesc
author2_role author
author
author
author
author
author
author
dc.subject.none.fl_str_mv Teoria del funcional de densitat
Catàlisi heterogènia
Carburs
Density functionals
Heterogeneus catalysis
Carbides
topic Teoria del funcional de densitat
Catàlisi heterogènia
Carburs
Density functionals
Heterogeneus catalysis
Carbides
description Experimental and theoretical evidences show that carbon vacancies determine the catalytic behavior of vanadium carbides in the CO2 conversion to CO via the Reverse Water Gas Shift (RWGS) reaction. Two VCx samples, one mostly containing stoichiometric VC and the other being C deficient, mainly V8C7, were synthesized, characterized, and studied. The samples show different CO2 adsorption heats, which correlate with those calculated using Density Functional Theory (DFT) on suitable models. The sample containing more V8C7 shows a higher CO2 conversion and CO selectivity and a lower apparent activation energy, being a stable catalyst over long-time tests. DFT calculations confirm that C vacancies in V8C7 are responsible for the observed catalytic behavior, allowing reactants to adsorb more strongly and lowering the energy barrier for both H2 and CO2 dissociation steps. The present work highlights the importance of such native point defects in the transition metal carbides surface chemistry and catalytic properties
publishDate 2020
dc.date.none.fl_str_mv 2020
dc.type.none.fl_str_mv info:eu-repo/semantics/article
info:eu-repo/semantics/acceptedVersion
format article
status_str acceptedVersion
dc.identifier.none.fl_str_mv https://hdl.handle.net/2445/165779
url https://hdl.handle.net/2445/165779
dc.language.none.fl_str_mv Inglés
language_invalid_str_mv Inglés
dc.relation.none.fl_str_mv Versió postprint del document publicat a: https://doi.org/10.1016/j.apcatb.2020.118719
Applied Catalysis B-Environmental, 2020, vol. 267, p. 118719 -1-118719-10
https://doi.org/10.1016/j.apcatb.2020.118719
dc.rights.none.fl_str_mv cc-by-nc-nd (c) Elsevier B.V., 2020
http://creativecommons.org/licenses/by-nc-nd/3.0/es
info:eu-repo/semantics/openAccess
rights_invalid_str_mv cc-by-nc-nd (c) Elsevier B.V., 2020
http://creativecommons.org/licenses/by-nc-nd/3.0/es
eu_rights_str_mv openAccess
dc.format.none.fl_str_mv application/pdf
dc.publisher.none.fl_str_mv Elsevier B.V.
publisher.none.fl_str_mv Elsevier B.V.
dc.source.none.fl_str_mv Articles publicats en revistes (Ciència dels Materials i Química Física)
reponame:Dipòsit Digital de la UB
instname:Universidad de Barcelona
instname_str Universidad de Barcelona
reponame_str Dipòsit Digital de la UB
collection Dipòsit Digital de la UB
repository.name.fl_str_mv
repository.mail.fl_str_mv
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