Time-resolved X-ray powder diffraction on a three-way catalyst at the GILDA beamline.

Détails

ID Serval
serval:BIB_92178DF0A7A9
Type
Article: article d'un périodique ou d'un magazine.
Collection
Publications
Titre
Time-resolved X-ray powder diffraction on a three-way catalyst at the GILDA beamline.
Périodique
Journal of Synchrotron Radiation
Auteur(s)
Martorana A., Deganello G., Longo A., Deganello F., Liotta L., Macaluso A., Pantaleo G., Balerna A., Meneghini C., Mobilio S.
ISSN
0909-0495
Statut éditorial
Publié
Date de publication
03/2003
Peer-reviewed
Oui
Volume
10
Numéro
2
Pages
177-182
Langue
anglais
Notes
Publication types: Journal Article - Publication Status: ppublish
Résumé
Time-resolved X-ray diffraction experiments carried out at the beamline BM08-GILDA of ESRF allowed a study of the structural modifications taking place in a Pt/ceria-zirconia catalyst while the CO oxidation reaction was in progress. The capillary tube in which the sample is stored acts effectively as a chemical microreactor that ensures homogeneity of the sample treatments and minimization of diffusion effects. During the flowing of the reactant CO/He mixture, the investigated catalyst undergoes a fast Ce(IV)-Ce(III) partial reduction that involves the release of one O atom for every two reduced Ce cations. Because Ce(III) has a larger ionic radius than Ce(IV), the structural modification produces an increase of the lattice constant of the ceria-zirconia mixed oxide, and this increase is monitored by the translating imaging-plate device implemented at GILDA. The CO(2) resulting from the oxidation of the fluxed CO is monitored by a quadrupole mass spectrometer during the recording of the time-resolved X-ray diffraction pattern. The chemical and structural information was combined to show that the CO(2) yield is nearly constant until the catalytic system can provide oxygen for the reaction, while the structural rearrangement of the catalyst is delayed with respect to the switching on of the CO/He flux. After this induction time, during which CO(2) is produced with no structural modification of the catalyst, a fast increase of the lattice constant takes place.
Pubmed
Web of science
Création de la notice
25/01/2008 16:13
Dernière modification de la notice
03/03/2018 19:30
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