Methodical aspects in the surface analysis of supported molybdena catalysts

Autores
Briand, Laura Estefania; Tkachenko, Olga P.; Guraya, Monica; Wachs, Israel E.; Grünert, Wolfgang
Año de publicación
2004
Idioma
inglés
Tipo de recurso
artículo
Estado
versión publicada
Descripción
Supported molybdena catalysts, with TiO2, CeO2 and Al2O3 supports, were studied by XPS and ISS. It was found that reliable results are obtained only when samples are calcined and transferred into the ultrahigh vacuum system without further contact with the ambient atmosphere ('in situ calcination'). This applies also to catalysts that were previously calcined but had been stored in the ambient atmosphere. Supported Mo oxide becomes reduced under x-ray irradiation during extended XPS data acquisition. A slight decrease of the Mo/support cation intensity ratio as a consequence of this reduction was detected by ISS in MoO3/TiO 2 and MoO3/CeO2, therefore ISS analysis should be performed on freshly calcined samples without prior extended exposure to x-rays. Because ISS spectra change rapidly due to sputtering, a correct analysis of the surface properties of the supported Mo catalyst requires extrapolation of the trend to the start of the experiment. It was established by this methodology that the surface of a 7% MoO3/TiO2 catalyst (5.3 Mo nm-2) is completely covered by a monolayer of Mo oxide species, and no Ti cation is exposed. In a submonolayer MoO3/CeO 2 catalyst the exposed support could be detected, as expected, whereas in an MoO3/Al2O3 catalyst with an Mo oxide loading equal to the monolayer coverage a slight exposure of the Al support cation also was noted probably because of the high curvature of the smaller Al2O3 particles. Copyright © 2004 John Wiley & Sons, Ltd.
Fil: Briand, Laura Estefania. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata. Centro de Investigación y Desarrollo en Ciencias Aplicadas "Dr. Jorge J. Ronco". Universidad Nacional de la Plata. Facultad de Ciencias Exactas. Centro de Investigación y Desarrollo en Ciencias Aplicadas; Argentina
Fil: Tkachenko, Olga P.. Russian Academy of Sciences; Rusia. Ruhr Universität Bochum; Alemania
Fil: Guraya, Monica. Comisión Nacional de Energía Atómica. Centro Atómico Bariloche; Argentina
Fil: Wachs, Israel E.. Lehigh University; Estados Unidos
Fil: Grünert, Wolfgang. Ruhr Universität Bochum; Alemania
Materia
Iss
Molybdena
Supported Catalysts
Xps
Nivel de accesibilidad
acceso abierto
Condiciones de uso
https://creativecommons.org/licenses/by-nc-sa/2.5/ar/
Repositorio
CONICET Digital (CONICET)
Institución
Consejo Nacional de Investigaciones Científicas y Técnicas
OAI Identificador
oai:ri.conicet.gov.ar:11336/62095
Acceder
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network_name_str CONICET Digital (CONICET)
spelling Methodical aspects in the surface analysis of supported molybdena catalystsBriand, Laura EstefaniaTkachenko, Olga P.Guraya, MonicaWachs, Israel E.Grünert, WolfgangIssMolybdenaSupported CatalystsXpshttps://purl.org/becyt/ford/2.4https://purl.org/becyt/ford/2Supported molybdena catalysts, with TiO2, CeO2 and Al2O3 supports, were studied by XPS and ISS. It was found that reliable results are obtained only when samples are calcined and transferred into the ultrahigh vacuum system without further contact with the ambient atmosphere ('in situ calcination'). This applies also to catalysts that were previously calcined but had been stored in the ambient atmosphere. Supported Mo oxide becomes reduced under x-ray irradiation during extended XPS data acquisition. A slight decrease of the Mo/support cation intensity ratio as a consequence of this reduction was detected by ISS in MoO3/TiO 2 and MoO3/CeO2, therefore ISS analysis should be performed on freshly calcined samples without prior extended exposure to x-rays. Because ISS spectra change rapidly due to sputtering, a correct analysis of the surface properties of the supported Mo catalyst requires extrapolation of the trend to the start of the experiment. It was established by this methodology that the surface of a 7% MoO3/TiO2 catalyst (5.3 Mo nm-2) is completely covered by a monolayer of Mo oxide species, and no Ti cation is exposed. In a submonolayer MoO3/CeO 2 catalyst the exposed support could be detected, as expected, whereas in an MoO3/Al2O3 catalyst with an Mo oxide loading equal to the monolayer coverage a slight exposure of the Al support cation also was noted probably because of the high curvature of the smaller Al2O3 particles. Copyright © 2004 John Wiley & Sons, Ltd.Fil: Briand, Laura Estefania. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata. Centro de Investigación y Desarrollo en Ciencias Aplicadas "Dr. Jorge J. Ronco". Universidad Nacional de la Plata. Facultad de Ciencias Exactas. Centro de Investigación y Desarrollo en Ciencias Aplicadas; ArgentinaFil: Tkachenko, Olga P.. Russian Academy of Sciences; Rusia. Ruhr Universität Bochum; AlemaniaFil: Guraya, Monica. Comisión Nacional de Energía Atómica. Centro Atómico Bariloche; ArgentinaFil: Wachs, Israel E.. Lehigh University; Estados UnidosFil: Grünert, Wolfgang. Ruhr Universität Bochum; AlemaniaJohn Wiley & Sons Ltd2004-03info:eu-repo/semantics/articleinfo:eu-repo/semantics/publishedVersionhttp://purl.org/coar/resource_type/c_6501info:ar-repo/semantics/articuloapplication/pdfapplication/pdfhttp://hdl.handle.net/11336/62095Briand, Laura Estefania; Tkachenko, Olga P.; Guraya, Monica; Wachs, Israel E.; Grünert, Wolfgang; Methodical aspects in the surface analysis of supported molybdena catalysts; John Wiley & Sons Ltd; Surface and Interface Analysis; 36; 3; 3-2004; 238-2450142-2421CONICET DigitalCONICETenginfo:eu-repo/semantics/altIdentifier/doi/10.1002/sia.1679info:eu-repo/semantics/altIdentifier/url/https://onlinelibrary.wiley.com/doi/abs/10.1002/sia.1679info:eu-repo/semantics/openAccesshttps://creativecommons.org/licenses/by-nc-sa/2.5/ar/reponame:CONICET Digital (CONICET)instname:Consejo Nacional de Investigaciones Científicas y Técnicas2025-09-10T13:15:54Zoai:ri.conicet.gov.ar:11336/62095instacron:CONICETInstitucionalhttp://ri.conicet.gov.ar/Organismo científico-tecnológicoNo correspondehttp://ri.conicet.gov.ar/oai/requestdasensio@conicet.gov.ar; lcarlino@conicet.gov.arArgentinaNo correspondeNo correspondeNo correspondeopendoar:34982025-09-10 13:15:54.898CONICET Digital (CONICET) - Consejo Nacional de Investigaciones Científicas y Técnicasfalse
dc.title.none.fl_str_mv Methodical aspects in the surface analysis of supported molybdena catalysts
title Methodical aspects in the surface analysis of supported molybdena catalysts
spellingShingle Methodical aspects in the surface analysis of supported molybdena catalysts
Briand, Laura Estefania
Iss
Molybdena
Supported Catalysts
Xps
title_short Methodical aspects in the surface analysis of supported molybdena catalysts
title_full Methodical aspects in the surface analysis of supported molybdena catalysts
title_fullStr Methodical aspects in the surface analysis of supported molybdena catalysts
title_full_unstemmed Methodical aspects in the surface analysis of supported molybdena catalysts
title_sort Methodical aspects in the surface analysis of supported molybdena catalysts
dc.creator.none.fl_str_mv Briand, Laura Estefania
Tkachenko, Olga P.
Guraya, Monica
Wachs, Israel E.
Grünert, Wolfgang
author Briand, Laura Estefania
author_facet Briand, Laura Estefania
Tkachenko, Olga P.
Guraya, Monica
Wachs, Israel E.
Grünert, Wolfgang
author_role author
author2 Tkachenko, Olga P.
Guraya, Monica
Wachs, Israel E.
Grünert, Wolfgang
author2_role author
author
author
author
dc.subject.none.fl_str_mv Iss
Molybdena
Supported Catalysts
Xps
topic Iss
Molybdena
Supported Catalysts
Xps
purl_subject.fl_str_mv https://purl.org/becyt/ford/2.4
https://purl.org/becyt/ford/2
dc.description.none.fl_txt_mv Supported molybdena catalysts, with TiO2, CeO2 and Al2O3 supports, were studied by XPS and ISS. It was found that reliable results are obtained only when samples are calcined and transferred into the ultrahigh vacuum system without further contact with the ambient atmosphere ('in situ calcination'). This applies also to catalysts that were previously calcined but had been stored in the ambient atmosphere. Supported Mo oxide becomes reduced under x-ray irradiation during extended XPS data acquisition. A slight decrease of the Mo/support cation intensity ratio as a consequence of this reduction was detected by ISS in MoO3/TiO 2 and MoO3/CeO2, therefore ISS analysis should be performed on freshly calcined samples without prior extended exposure to x-rays. Because ISS spectra change rapidly due to sputtering, a correct analysis of the surface properties of the supported Mo catalyst requires extrapolation of the trend to the start of the experiment. It was established by this methodology that the surface of a 7% MoO3/TiO2 catalyst (5.3 Mo nm-2) is completely covered by a monolayer of Mo oxide species, and no Ti cation is exposed. In a submonolayer MoO3/CeO 2 catalyst the exposed support could be detected, as expected, whereas in an MoO3/Al2O3 catalyst with an Mo oxide loading equal to the monolayer coverage a slight exposure of the Al support cation also was noted probably because of the high curvature of the smaller Al2O3 particles. Copyright © 2004 John Wiley & Sons, Ltd.
Fil: Briand, Laura Estefania. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata. Centro de Investigación y Desarrollo en Ciencias Aplicadas "Dr. Jorge J. Ronco". Universidad Nacional de la Plata. Facultad de Ciencias Exactas. Centro de Investigación y Desarrollo en Ciencias Aplicadas; Argentina
Fil: Tkachenko, Olga P.. Russian Academy of Sciences; Rusia. Ruhr Universität Bochum; Alemania
Fil: Guraya, Monica. Comisión Nacional de Energía Atómica. Centro Atómico Bariloche; Argentina
Fil: Wachs, Israel E.. Lehigh University; Estados Unidos
Fil: Grünert, Wolfgang. Ruhr Universität Bochum; Alemania
description Supported molybdena catalysts, with TiO2, CeO2 and Al2O3 supports, were studied by XPS and ISS. It was found that reliable results are obtained only when samples are calcined and transferred into the ultrahigh vacuum system without further contact with the ambient atmosphere ('in situ calcination'). This applies also to catalysts that were previously calcined but had been stored in the ambient atmosphere. Supported Mo oxide becomes reduced under x-ray irradiation during extended XPS data acquisition. A slight decrease of the Mo/support cation intensity ratio as a consequence of this reduction was detected by ISS in MoO3/TiO 2 and MoO3/CeO2, therefore ISS analysis should be performed on freshly calcined samples without prior extended exposure to x-rays. Because ISS spectra change rapidly due to sputtering, a correct analysis of the surface properties of the supported Mo catalyst requires extrapolation of the trend to the start of the experiment. It was established by this methodology that the surface of a 7% MoO3/TiO2 catalyst (5.3 Mo nm-2) is completely covered by a monolayer of Mo oxide species, and no Ti cation is exposed. In a submonolayer MoO3/CeO 2 catalyst the exposed support could be detected, as expected, whereas in an MoO3/Al2O3 catalyst with an Mo oxide loading equal to the monolayer coverage a slight exposure of the Al support cation also was noted probably because of the high curvature of the smaller Al2O3 particles. Copyright © 2004 John Wiley & Sons, Ltd.
publishDate 2004
dc.date.none.fl_str_mv 2004-03
dc.type.none.fl_str_mv info:eu-repo/semantics/article
info:eu-repo/semantics/publishedVersion
http://purl.org/coar/resource_type/c_6501
info:ar-repo/semantics/articulo
format article
status_str publishedVersion
dc.identifier.none.fl_str_mv http://hdl.handle.net/11336/62095
Briand, Laura Estefania; Tkachenko, Olga P.; Guraya, Monica; Wachs, Israel E.; Grünert, Wolfgang; Methodical aspects in the surface analysis of supported molybdena catalysts; John Wiley & Sons Ltd; Surface and Interface Analysis; 36; 3; 3-2004; 238-245
0142-2421
CONICET Digital
CONICET
url http://hdl.handle.net/11336/62095
identifier_str_mv Briand, Laura Estefania; Tkachenko, Olga P.; Guraya, Monica; Wachs, Israel E.; Grünert, Wolfgang; Methodical aspects in the surface analysis of supported molybdena catalysts; John Wiley & Sons Ltd; Surface and Interface Analysis; 36; 3; 3-2004; 238-245
0142-2421
CONICET Digital
CONICET
dc.language.none.fl_str_mv eng
language eng
dc.relation.none.fl_str_mv info:eu-repo/semantics/altIdentifier/doi/10.1002/sia.1679
info:eu-repo/semantics/altIdentifier/url/https://onlinelibrary.wiley.com/doi/abs/10.1002/sia.1679
dc.rights.none.fl_str_mv info:eu-repo/semantics/openAccess
https://creativecommons.org/licenses/by-nc-sa/2.5/ar/
eu_rights_str_mv openAccess
rights_invalid_str_mv https://creativecommons.org/licenses/by-nc-sa/2.5/ar/
dc.format.none.fl_str_mv application/pdf
application/pdf
dc.publisher.none.fl_str_mv John Wiley & Sons Ltd
publisher.none.fl_str_mv John Wiley & Sons Ltd
dc.source.none.fl_str_mv reponame:CONICET Digital (CONICET)
instname:Consejo Nacional de Investigaciones Científicas y Técnicas
reponame_str CONICET Digital (CONICET)
collection CONICET Digital (CONICET)
instname_str Consejo Nacional de Investigaciones Científicas y Técnicas
repository.name.fl_str_mv CONICET Digital (CONICET) - Consejo Nacional de Investigaciones Científicas y Técnicas
repository.mail.fl_str_mv dasensio@conicet.gov.ar; lcarlino@conicet.gov.ar
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score 12.993085

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