Surface Characterisation of V2O5/TiO2 Catalytic System
Autor(a) principal: | |
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Data de Publicação: | 2001 |
Outros Autores: | , , , , |
Tipo de documento: | Artigo |
Idioma: | eng |
Título da fonte: | Repositório Institucional da UNESP |
Texto Completo: | http://dx.doi.org/10.1002/1521-396X(200109)187:1<161 http://hdl.handle.net/11449/223837 |
Resumo: | Samples of the V2O5/TiO2 system were prepared by the sol-gel method and calcined at different temperatures. Surface species of vanadium, their dispersion, as wefl as the structural evolution of the system were analysed by XRD, Raman, EPR, and XPS techniques. The results of XRD showed the evolution of TiO2 from anatase phase to rutile phase. The Raman spectra for calcination temperatures up to 500°C showed a good dispersion of vanadium over titania in the form of monomeric vanadyl groups (V4+) and polymeric vanadates (V5+). At least three families of V4+ ions were identified by EPR investigations. Two kinds of isolated V4+ species are placed in sites of octahedral symmetry, substituting Ti4+ in the rutile phase. The third is formed by pairs of V4+ species on the surface of titania. Above 500°C part of superficial V4+ is inserted into the matrix of titania and part is oxidized to V5+. The XPS results showed that the V/Ti ratio rises with increasing calcination temperature, indicating a smaller dispersion of vanadium. |
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Repositório Institucional da UNESP |
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Surface Characterisation of V2O5/TiO2 Catalytic SystemSamples of the V2O5/TiO2 system were prepared by the sol-gel method and calcined at different temperatures. Surface species of vanadium, their dispersion, as wefl as the structural evolution of the system were analysed by XRD, Raman, EPR, and XPS techniques. The results of XRD showed the evolution of TiO2 from anatase phase to rutile phase. The Raman spectra for calcination temperatures up to 500°C showed a good dispersion of vanadium over titania in the form of monomeric vanadyl groups (V4+) and polymeric vanadates (V5+). At least three families of V4+ ions were identified by EPR investigations. Two kinds of isolated V4+ species are placed in sites of octahedral symmetry, substituting Ti4+ in the rutile phase. The third is formed by pairs of V4+ species on the surface of titania. Above 500°C part of superficial V4+ is inserted into the matrix of titania and part is oxidized to V5+. The XPS results showed that the V/Ti ratio rises with increasing calcination temperature, indicating a smaller dispersion of vanadium.Depto. de Fis. e Cie. dos Materiais Inst. de Fis. de São Carlos Universidade de São Paulo, CEP 13560-970, São Carlos, SPCtro. Caracterizacao D. Depto. de Engenharia de Materiais Univ. Federal de São Carlos, CEP 13565-905, São Carlos, SPDepartamento de Química Instituto de Biociências Universidade Estadual Paulista, CEP 18618-000, Botucatu, SPDepartamento de Química Instituto de Biociências Universidade Estadual Paulista, CEP 18618-000, Botucatu, SPUniversidade de São Paulo (USP)Universidade Federal de São Carlos (UFSCar)Universidade Estadual Paulista (UNESP)Rodella, C. B.Nascente, P. A.P.Franco, R. W.A.Magon, C. J.Mastelaro, V. R.Florentino, A. O. [UNESP]2022-04-28T19:53:20Z2022-04-28T19:53:20Z2001-09-01info:eu-repo/semantics/publishedVersioninfo:eu-repo/semantics/article161-169http://dx.doi.org/10.1002/1521-396X(200109)187:1<161Physica Status Solidi (A) Applied Research, v. 187, n. 1, p. 161-169, 2001.0031-8965http://hdl.handle.net/11449/22383710.1002/1521-396X(200109)187:1<1612-s2.0-0001538187Scopusreponame:Repositório Institucional da UNESPinstname:Universidade Estadual Paulista (UNESP)instacron:UNESPengPhysica Status Solidi (A) Applied Researchinfo:eu-repo/semantics/openAccess2022-04-28T19:53:20Zoai:repositorio.unesp.br:11449/223837Repositório InstitucionalPUBhttp://repositorio.unesp.br/oai/requestopendoar:29462022-04-28T19:53:20Repositório Institucional da UNESP - Universidade Estadual Paulista (UNESP)false |
dc.title.none.fl_str_mv |
Surface Characterisation of V2O5/TiO2 Catalytic System |
title |
Surface Characterisation of V2O5/TiO2 Catalytic System |
spellingShingle |
Surface Characterisation of V2O5/TiO2 Catalytic System Rodella, C. B. |
title_short |
Surface Characterisation of V2O5/TiO2 Catalytic System |
title_full |
Surface Characterisation of V2O5/TiO2 Catalytic System |
title_fullStr |
Surface Characterisation of V2O5/TiO2 Catalytic System |
title_full_unstemmed |
Surface Characterisation of V2O5/TiO2 Catalytic System |
title_sort |
Surface Characterisation of V2O5/TiO2 Catalytic System |
author |
Rodella, C. B. |
author_facet |
Rodella, C. B. Nascente, P. A.P. Franco, R. W.A. Magon, C. J. Mastelaro, V. R. Florentino, A. O. [UNESP] |
author_role |
author |
author2 |
Nascente, P. A.P. Franco, R. W.A. Magon, C. J. Mastelaro, V. R. Florentino, A. O. [UNESP] |
author2_role |
author author author author author |
dc.contributor.none.fl_str_mv |
Universidade de São Paulo (USP) Universidade Federal de São Carlos (UFSCar) Universidade Estadual Paulista (UNESP) |
dc.contributor.author.fl_str_mv |
Rodella, C. B. Nascente, P. A.P. Franco, R. W.A. Magon, C. J. Mastelaro, V. R. Florentino, A. O. [UNESP] |
description |
Samples of the V2O5/TiO2 system were prepared by the sol-gel method and calcined at different temperatures. Surface species of vanadium, their dispersion, as wefl as the structural evolution of the system were analysed by XRD, Raman, EPR, and XPS techniques. The results of XRD showed the evolution of TiO2 from anatase phase to rutile phase. The Raman spectra for calcination temperatures up to 500°C showed a good dispersion of vanadium over titania in the form of monomeric vanadyl groups (V4+) and polymeric vanadates (V5+). At least three families of V4+ ions were identified by EPR investigations. Two kinds of isolated V4+ species are placed in sites of octahedral symmetry, substituting Ti4+ in the rutile phase. The third is formed by pairs of V4+ species on the surface of titania. Above 500°C part of superficial V4+ is inserted into the matrix of titania and part is oxidized to V5+. The XPS results showed that the V/Ti ratio rises with increasing calcination temperature, indicating a smaller dispersion of vanadium. |
publishDate |
2001 |
dc.date.none.fl_str_mv |
2001-09-01 2022-04-28T19:53:20Z 2022-04-28T19:53:20Z |
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/10.1002/1521-396X(200109)187:1<161 Physica Status Solidi (A) Applied Research, v. 187, n. 1, p. 161-169, 2001. 0031-8965 http://hdl.handle.net/11449/223837 10.1002/1521-396X(200109)187:1<161 2-s2.0-0001538187 |
url |
http://dx.doi.org/10.1002/1521-396X(200109)187:1<161 http://hdl.handle.net/11449/223837 |
identifier_str_mv |
Physica Status Solidi (A) Applied Research, v. 187, n. 1, p. 161-169, 2001. 0031-8965 10.1002/1521-396X(200109)187:1<161 2-s2.0-0001538187 |
dc.language.iso.fl_str_mv |
eng |
language |
eng |
dc.relation.none.fl_str_mv |
Physica Status Solidi (A) Applied Research |
dc.rights.driver.fl_str_mv |
info:eu-repo/semantics/openAccess |
eu_rights_str_mv |
openAccess |
dc.format.none.fl_str_mv |
161-169 |
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_ |
1803046590308417536 |