Structure of catalysts: Determination by EPR and Fourier analysis of the extended x‐ray absorption fine structure
作者:
Farrel W. Lytle,
Dale E. Sayers,
Emmett B. Moore,
期刊:
Applied Physics Letters
(AIP Available online 1974)
卷期:
Volume 24,
issue 2
页码: 45-47
ISSN:0003-6951
年代: 1974
DOI:10.1063/1.1655087
出版商: AIP
数据来源: AIP
摘要:
An alumina‐supported CuCr catalyst was examined with the extended x‐ray absorption fine‐structure (EXAFS) technique. This is a new technique which can determine the chemical states and near‐neighbor environments of the separate Cu and Cr atomic species. Cu was found to occupy both tetrahedral and octahedral sites in the supporting alumina lattice while Cr was found only in octahedral sites. The valence state was Cr+5in the fresh catalyst which changed to Cr+6in the exhaust‐cycled material. Confirmation of the valence state assignment was obtained by EPR. Fourier analysis of the EXAFS produced separate radial structure functions for the Cu and Cr atoms since the experiment measures the properties of the individual atomic species rather than those of the structure as a whole. Significant differences were observed by both techniques between fresh and exhaust‐cycled material.
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