Insights into Redox Dynamics of Vanadium Species Impregnated in Layered Siliceous Zeolitic Structures during Methanol Oxidation Reactions
Autor(a) principal: | |
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Data de Publicação: | 2020 |
Outros Autores: | , , , , , |
Tipo de documento: | Artigo |
Idioma: | eng |
Título da fonte: | Repositório Institucional da UNESP |
Texto Completo: | http://dx.doi.org/10.1002/cctc.201901567 http://hdl.handle.net/11449/198097 |
Resumo: | Supported transition metal catalysts have been extensively applied to oxidative and reductive processes. The understanding of surface speciation and active site-support interactions in these materials play a substantial role in developing improved heterogeneous catalysts. Herein, a series of impregnated 3D ferrierite and 2D ITQ-6 siliceous supports with variable loading of vanadium oxide was prepared. Chemical and structural properties of the materials were studied by X-ray diffraction, N2 physisorption, inductively coupled plasma – optical emission spectrometry, X-ray absorption, Fourier transform infrared and diffuse reflectance UV-vis spectroscopies, and temperature-programmed reduction with H2. Reactivity of the catalyst surface, associated with the incidence of isolated silanol groups, was found to be more effective when vanadium oxides were better dispersed and stabilized than increases in surface area. Differences in activation and the oxidation state dynamic behavior of active sites were then probed by methanol oxidation as a model reaction monitored by in situ FTIR spectroscopy and XANES/MS. By applying isothermal periods of reaction under non-oxidizing atmosphere and regeneration of catalysts by O2, it was found that, even at distinct rates, all types of sites are accessible during reaction, since a complete reduction to V4+ was observed. However, reoxidation of sites to V5+ is limited and sensitive to the different vanadium species on the surface, and probably, the determinant factor of the distinct V5+/V4+ equilibrium reached for the catalysts when the reaction is carried out under constant oxidizing atmosphere. |
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Insights into Redox Dynamics of Vanadium Species Impregnated in Layered Siliceous Zeolitic Structures during Methanol Oxidation Reactionslamellar materialmethanoloxidationvanadiumzeolite structureSupported transition metal catalysts have been extensively applied to oxidative and reductive processes. The understanding of surface speciation and active site-support interactions in these materials play a substantial role in developing improved heterogeneous catalysts. Herein, a series of impregnated 3D ferrierite and 2D ITQ-6 siliceous supports with variable loading of vanadium oxide was prepared. Chemical and structural properties of the materials were studied by X-ray diffraction, N2 physisorption, inductively coupled plasma – optical emission spectrometry, X-ray absorption, Fourier transform infrared and diffuse reflectance UV-vis spectroscopies, and temperature-programmed reduction with H2. Reactivity of the catalyst surface, associated with the incidence of isolated silanol groups, was found to be more effective when vanadium oxides were better dispersed and stabilized than increases in surface area. Differences in activation and the oxidation state dynamic behavior of active sites were then probed by methanol oxidation as a model reaction monitored by in situ FTIR spectroscopy and XANES/MS. By applying isothermal periods of reaction under non-oxidizing atmosphere and regeneration of catalysts by O2, it was found that, even at distinct rates, all types of sites are accessible during reaction, since a complete reduction to V4+ was observed. However, reoxidation of sites to V5+ is limited and sensitive to the different vanadium species on the surface, and probably, the determinant factor of the distinct V5+/V4+ equilibrium reached for the catalysts when the reaction is carried out under constant oxidizing atmosphere.Instituto de Química Universidade Estadual Paulista – UNESP, R. Prof. Francisco Degni, 55School of Chemical & Biomolecular Engineering Georgia Institute of Technology, 311 Ferst Drive NWInstituto de Química Universidade Estadual Paulista – UNESP, R. Prof. Francisco Degni, 55Universidade Estadual Paulista (Unesp)Georgia Institute of TechnologyVieira, Luiz H. [UNESP]Possato, Luiz G. [UNESP]Chaves, Thiago F. [UNESP]Lee, Jason J.Sulmonetti, Taylor P.Jones, Christopher W.Martins, Leandro [UNESP]2020-12-12T00:59:05Z2020-12-12T00:59:05Z2020-01-08info:eu-repo/semantics/publishedVersioninfo:eu-repo/semantics/article141-151http://dx.doi.org/10.1002/cctc.201901567ChemCatChem, v. 12, n. 1, p. 141-151, 2020.1867-38991867-3880http://hdl.handle.net/11449/19809710.1002/cctc.2019015672-s2.0-85074643752Scopusreponame:Repositório Institucional da UNESPinstname:Universidade Estadual Paulista (UNESP)instacron:UNESPengChemCatCheminfo:eu-repo/semantics/openAccess2021-10-23T08:38:59Zoai:repositorio.unesp.br:11449/198097Repositório InstitucionalPUBhttp://repositorio.unesp.br/oai/requestopendoar:29462021-10-23T08:38:59Repositório Institucional da UNESP - Universidade Estadual Paulista (UNESP)false |
dc.title.none.fl_str_mv |
Insights into Redox Dynamics of Vanadium Species Impregnated in Layered Siliceous Zeolitic Structures during Methanol Oxidation Reactions |
title |
Insights into Redox Dynamics of Vanadium Species Impregnated in Layered Siliceous Zeolitic Structures during Methanol Oxidation Reactions |
spellingShingle |
Insights into Redox Dynamics of Vanadium Species Impregnated in Layered Siliceous Zeolitic Structures during Methanol Oxidation Reactions Vieira, Luiz H. [UNESP] lamellar material methanol oxidation vanadium zeolite structure |
title_short |
Insights into Redox Dynamics of Vanadium Species Impregnated in Layered Siliceous Zeolitic Structures during Methanol Oxidation Reactions |
title_full |
Insights into Redox Dynamics of Vanadium Species Impregnated in Layered Siliceous Zeolitic Structures during Methanol Oxidation Reactions |
title_fullStr |
Insights into Redox Dynamics of Vanadium Species Impregnated in Layered Siliceous Zeolitic Structures during Methanol Oxidation Reactions |
title_full_unstemmed |
Insights into Redox Dynamics of Vanadium Species Impregnated in Layered Siliceous Zeolitic Structures during Methanol Oxidation Reactions |
title_sort |
Insights into Redox Dynamics of Vanadium Species Impregnated in Layered Siliceous Zeolitic Structures during Methanol Oxidation Reactions |
author |
Vieira, Luiz H. [UNESP] |
author_facet |
Vieira, Luiz H. [UNESP] Possato, Luiz G. [UNESP] Chaves, Thiago F. [UNESP] Lee, Jason J. Sulmonetti, Taylor P. Jones, Christopher W. Martins, Leandro [UNESP] |
author_role |
author |
author2 |
Possato, Luiz G. [UNESP] Chaves, Thiago F. [UNESP] Lee, Jason J. Sulmonetti, Taylor P. Jones, Christopher W. Martins, Leandro [UNESP] |
author2_role |
author author author author author author |
dc.contributor.none.fl_str_mv |
Universidade Estadual Paulista (Unesp) Georgia Institute of Technology |
dc.contributor.author.fl_str_mv |
Vieira, Luiz H. [UNESP] Possato, Luiz G. [UNESP] Chaves, Thiago F. [UNESP] Lee, Jason J. Sulmonetti, Taylor P. Jones, Christopher W. Martins, Leandro [UNESP] |
dc.subject.por.fl_str_mv |
lamellar material methanol oxidation vanadium zeolite structure |
topic |
lamellar material methanol oxidation vanadium zeolite structure |
description |
Supported transition metal catalysts have been extensively applied to oxidative and reductive processes. The understanding of surface speciation and active site-support interactions in these materials play a substantial role in developing improved heterogeneous catalysts. Herein, a series of impregnated 3D ferrierite and 2D ITQ-6 siliceous supports with variable loading of vanadium oxide was prepared. Chemical and structural properties of the materials were studied by X-ray diffraction, N2 physisorption, inductively coupled plasma – optical emission spectrometry, X-ray absorption, Fourier transform infrared and diffuse reflectance UV-vis spectroscopies, and temperature-programmed reduction with H2. Reactivity of the catalyst surface, associated with the incidence of isolated silanol groups, was found to be more effective when vanadium oxides were better dispersed and stabilized than increases in surface area. Differences in activation and the oxidation state dynamic behavior of active sites were then probed by methanol oxidation as a model reaction monitored by in situ FTIR spectroscopy and XANES/MS. By applying isothermal periods of reaction under non-oxidizing atmosphere and regeneration of catalysts by O2, it was found that, even at distinct rates, all types of sites are accessible during reaction, since a complete reduction to V4+ was observed. However, reoxidation of sites to V5+ is limited and sensitive to the different vanadium species on the surface, and probably, the determinant factor of the distinct V5+/V4+ equilibrium reached for the catalysts when the reaction is carried out under constant oxidizing atmosphere. |
publishDate |
2020 |
dc.date.none.fl_str_mv |
2020-12-12T00:59:05Z 2020-12-12T00:59:05Z 2020-01-08 |
dc.type.status.fl_str_mv |
info:eu-repo/semantics/publishedVersion |
dc.type.driver.fl_str_mv |
info:eu-repo/semantics/article |
format |
article |
status_str |
publishedVersion |
dc.identifier.uri.fl_str_mv |
http://dx.doi.org/10.1002/cctc.201901567 ChemCatChem, v. 12, n. 1, p. 141-151, 2020. 1867-3899 1867-3880 http://hdl.handle.net/11449/198097 10.1002/cctc.201901567 2-s2.0-85074643752 |
url |
http://dx.doi.org/10.1002/cctc.201901567 http://hdl.handle.net/11449/198097 |
identifier_str_mv |
ChemCatChem, v. 12, n. 1, p. 141-151, 2020. 1867-3899 1867-3880 10.1002/cctc.201901567 2-s2.0-85074643752 |
dc.language.iso.fl_str_mv |
eng |
language |
eng |
dc.relation.none.fl_str_mv |
ChemCatChem |
dc.rights.driver.fl_str_mv |
info:eu-repo/semantics/openAccess |
eu_rights_str_mv |
openAccess |
dc.format.none.fl_str_mv |
141-151 |
dc.source.none.fl_str_mv |
Scopus reponame:Repositório Institucional da UNESP instname:Universidade Estadual Paulista (UNESP) instacron:UNESP |
instname_str |
Universidade Estadual Paulista (UNESP) |
instacron_str |
UNESP |
institution |
UNESP |
reponame_str |
Repositório Institucional da UNESP |
collection |
Repositório Institucional da UNESP |
repository.name.fl_str_mv |
Repositório Institucional da UNESP - Universidade Estadual Paulista (UNESP) |
repository.mail.fl_str_mv |
|
_version_ |
1803649767736082432 |