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Structural Defects In Cerium Oxide Catalytic Support Studied by Pulsed Neutron Diffraction

Published online by Cambridge University Press:  15 February 2011

E. Mamontov ,
T. Egami  and
R. Brezny
E. Mamontov
Affiliation:
MSE Department, University of Pennsylvania, Philadelphia, PA 19104, mamontov@soll.lrsm.upenn.edu
T. Egami
Affiliation:
MSE Department, University of Pennsylvania, Philadelphia, PA 19104, mamontov@soll.lrsm.upenn.edu
R. Brezny
Affiliation:
Grace Davison, Columbia, MD 21044
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Abstract

We studied the structure of coarse and nano-scale powders of CeO2 using pulsed neutron scattering. The diffraction data were analyzed using Rietveld refinement, and were also Fourier-transformed to obtain the pair-distribution function (PDF). The Frenkel type oxygen defects consisting of vacancies in the oxygen sublattice and oxygen ions in the octahedral interstitial sites of the fluorite structure were observed in cerium oxide for the first time. The interstitial oxygen ions were found to recombine with vacancies when the sample underwent thermal treatment at 1073 K. We suggest that these defects are directly involved in the oxygen storage mechanism of ceria used in automotive catalytic converters.

Type
Research Article
Information
MRS Online Proceedings Library (OPL) , Volume 549: Symposium FF – Advanced Catalytic Materials - 1998 , 1998 , 185
Copyright
Copyright © Materials Research Society 1999

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