Titre :

EXAFS spectroscopy as a tool to probe metal-support interaction and surface molecular structures in oxide-supported catalysts: application to Al2O3-supported Ni(II) complexes and ZrO2-supported tungstates

Auteur(s) :

Carrier, X. [Auteur]
Marceau, Eric [Auteur]
Unité de Catalyse et Chimie du Solide (UCCS) - UMR 8181
Carabineiro, H. [Auteur]
Rodriguez-Gonzalez, V. [Auteur]
Che, M. [Auteur]

Titre de la revue :

Phys. Chem. Chem. Phys.

Nom court de la revue :

Phys. Chem. Chem. Phys.

Pagination :

7527-7539

Date de publication :

2009-06-25

ISSN :

1463-9076

Discipline(s) HAL :

Chimie

Résumé en anglais : [en]

EXAFS spectroscopy is shown as a tool of prime importance to probe the formation of metal–oxygen–support bonds and unravel the surface molecular structure in oxide-supported systems through two examples: (i) a molecular ...
Lire la suite >EXAFS spectroscopy is shown as a tool of prime importance to probe the formation of metal–oxygen–support bonds and unravel the surface molecular structure in oxide-supported systems through two examples: (i) a molecular metal complex (Ni(II) bisglycinate) characterized after impregnation and drying on Al2O3, and (ii) a tungsten oxide nanophase characterized after deposition on zirconia and high temperature thermal treatment (tungstated zirconia catalysts, i.e. WOx/ZrO2). Unlike other spectroscopic techniques, EXAFS at the Ni K-edge proves that a modest thermal activation during the impregnation step triggers the grafting of nickel(II) bisglycinate onto the support: Al next-nearest neighbours are detected when the impregnation is carried out at 60 °C instead of room temperature. Characterization of WOx/ZrO2 catalysts shows the presence of W next-nearest neighbours around tungsten, with W–W distances distinctive of edge-shared WO6 octahedra only. The WOx overlayer can thus be described as bidimensional, nanometric slabs of 4 to 5 WO6 units on each side. In these slabs, W octahedra are interconnected to form a more condensed structure than the one present in bulk WO3 (in which linkage through corners exists). Moreover, EXAFS results conclusively demonstrate that the WOx overlayer is directly anchored to the ZrO2 surface by means of W–O–Zr bonds with a W–Zr distance of 3.14 Å.Lire moins >

Langue :

Anglais

Établissement(s) :

Université de Lille
CNRS
Centrale Lille
ENSCL
Univ. Artois

Collections :

• Unité de Catalyse et Chimie du Solide (UCCS) - UMR 8181

Équipe(s) de recherche :

Matériaux pour la catalyse (MATCAT)

Date de dépôt :

2023-05-30T17:57:18Z