Metal-support interaction and redox behavior of Pt(1 wt %)/Ce0.6Zr0.4O2.

Details

Serval ID
serval:BIB_9F4D31EFE87A
Type
Article: article from journal or magazin.
Collection
Publications
Institution
Title
Metal-support interaction and redox behavior of Pt(1 wt %)/Ce0.6Zr0.4O2.
Journal
Journal of Physical Chemistry. B
Author(s)
Deganello G., Giannici F., Martorana A., Pantaleo G., Prestianni A., Balerna A., Liotta L.F., Longo A.
ISSN
1520-6106
Publication state
Published
Issued date
05/2006
Peer-reviewed
Oui
Volume
110
Number
17
Pages
8731-8739
Language
english
Abstract
The catalyst Pt(1 wt %)/Ce(0.6)Zr(0.4)O(2) is studied by CO-temperature programmed reduction (CO-TPR), isothermal oxygen storage complete capacity (OSCC), X-ray absorption spectroscopy (XAS) at the Pt L(III) edge, and in situ X-ray diffraction (in situ XRD), with the aim of elucidating the role of supported metal in CO oxidation by ceria-based three-way catalysts (TWC). The redox behavior of Pt(1 wt %)/Ce(0.6)Zr(0.4)O(2) is compared to that of bare ceria-zirconia. OSCC of redox-aged Pt/ceria-zirconia is twice that of bare ceria-zirconia, and the maximum of CO consumption occurs at a temperature about 300 K lower than redox-aged ceria-zirconia. XAS analysis allows one to evidence the formation of a platinum-cerium alloy in redox-aged samples and the stability of the metal particles toward oxidation and sintering during high-temperature treatments. Under CO flux at 773 K, bare ceria-zirconia shows a continuous drift of diffraction peaks toward smaller Bragg angles, due to a progressive increase of Ce(III) content. Under the same treatment, the structural rearrangement of Pt-supported ceria-zirconia starts after an induction time and takes place with an abrupt change of the lattice constant. The experimental evidence points to the role of supported Pt in modifying the redox properties of ceria-zirconia with respect to the bare support. It is proposed that the much faster bulk reduction observed by in situ XRD for redox-aged Pt/ceria-zirconia can be attributed to an easier release of reacted CO(2), producing a more effective turnover of reactants at the catalyst surface.
Pubmed
Web of science
Create date
25/01/2008 15:13
Last modification date
20/08/2019 15:05
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