Investigation of the reducibility of ...
Type de document :
Article dans une revue scientifique: Article original
DOI :
URL permanente :
Titre :
Investigation of the reducibility of supported oxomolybdate species for mapping of active centers of partial oxidation reaction: in situ mo k-edge xas and dft study
Auteur(s) :
Hu, Hao [Auteur]
De Souza, Danilo Oliveira [Auteur]
Berrier, Elise [Auteur]
Paul, Jean-Francois [Auteur]
Unité de Catalyse et Chimie du Solide (UCCS) - UMR 8181
La Fontaine, Camille [Auteur]
Briois, Valerie [Auteur]
Cristol, Sylvain [Auteur]
Unité de Catalyse et Chimie du Solide (UCCS) - UMR 8181
Tougerti, Asma [Auteur]
Unité de Catalyse et Chimie du Solide (UCCS) - UMR 8181
De Souza, Danilo Oliveira [Auteur]
Berrier, Elise [Auteur]
Paul, Jean-Francois [Auteur]
Unité de Catalyse et Chimie du Solide (UCCS) - UMR 8181
La Fontaine, Camille [Auteur]
Briois, Valerie [Auteur]
Cristol, Sylvain [Auteur]
Unité de Catalyse et Chimie du Solide (UCCS) - UMR 8181
Tougerti, Asma [Auteur]
Unité de Catalyse et Chimie du Solide (UCCS) - UMR 8181
Titre de la revue :
The journal of physical chemistry. C, Nanomaterials and interfaces
Nom court de la revue :
J. Phys. Chem. C
Numéro :
123
Pagination :
18325-18335
Date de publication :
2019-07-22
ISSN :
1932-7447
Discipline(s) HAL :
Chimie/Chimie théorique et/ou physique
Résumé en anglais : [en]
We have investigated the molecular and electronic structure of a TiO2-supported oxomolybdate phase upon reduction under methanol or dihydrogen atmosphere. In situ Mo K-edge X-ray absorption spectroscopy, supported by density ...
Lire la suite >We have investigated the molecular and electronic structure of a TiO2-supported oxomolybdate phase upon reduction under methanol or dihydrogen atmosphere. In situ Mo K-edge X-ray absorption spectroscopy, supported by density functional theory (DFT) calculations and ab initio X-ray absorption spectroscopy (XAS) spectra simulation showed that the reducibility of supported molybdate species is closely related to the geometric environment of Mo atoms. Indeed, Mo atoms not involved in terminal oxo sites are easily reducible whereas Mo dioxo species are not under the conditions we have applied. Between those extreme cases, Mo atoms involved in mono-oxo terminal sites exhibit intermediate reducibility, which varies according to their local environment and their interaction with the support. Spin density calculations showed that under CH3OH flow, the surface of the catalyst is partially reduced. The structure of the reduced phase after reaction with methanol was compared to that afforded after reduction by dihydrogen. Our results show that the reduction under H2 flow does not increase the number of reduced Mo atoms but causes a higher spin density per Mo atom. On the basis of the individual mapping of the electronic structure of Mo species as drawn by DFT and XAS spectra simulation, a model that details the structure of the Mo active sites in the selective oxidation of methanol is proposed.Lire moins >
Lire la suite >We have investigated the molecular and electronic structure of a TiO2-supported oxomolybdate phase upon reduction under methanol or dihydrogen atmosphere. In situ Mo K-edge X-ray absorption spectroscopy, supported by density functional theory (DFT) calculations and ab initio X-ray absorption spectroscopy (XAS) spectra simulation showed that the reducibility of supported molybdate species is closely related to the geometric environment of Mo atoms. Indeed, Mo atoms not involved in terminal oxo sites are easily reducible whereas Mo dioxo species are not under the conditions we have applied. Between those extreme cases, Mo atoms involved in mono-oxo terminal sites exhibit intermediate reducibility, which varies according to their local environment and their interaction with the support. Spin density calculations showed that under CH3OH flow, the surface of the catalyst is partially reduced. The structure of the reduced phase after reaction with methanol was compared to that afforded after reduction by dihydrogen. Our results show that the reduction under H2 flow does not increase the number of reduced Mo atoms but causes a higher spin density per Mo atom. On the basis of the individual mapping of the electronic structure of Mo species as drawn by DFT and XAS spectra simulation, a model that details the structure of the Mo active sites in the selective oxidation of methanol is proposed.Lire moins >
Langue :
Anglais
Audience :
Internationale
Vulgarisation :
Non
Établissement(s) :
CNRS
Centrale Lille
ENSCL
Univ. Artois
Université de Lille
Centrale Lille
ENSCL
Univ. Artois
Université de Lille
Collections :
Équipe(s) de recherche :
Modélisation et spectroscopies (MODSPEC)
Date de dépôt :
2022-03-02T07:13:23Z