INVESTIGADORES
DE MIGUEL sergio Ruben
artículos
Título:
XAFS Study of Dried and Reduced PtSn/C Catalysts: Nature and Structure of the Catalytically Active Phase
Autor/es:
M. C. ROMAN-MARTINEZ; D. CAZORLA-AMOROS; H. YAMASHITA; S. DE MIGUEL; O. A. SCELZA
Revista:
LANGMUIR
Editorial:
American Chemical Society
Referencias:
Año: 2000 vol. 16 p. 1123 - 1131
ISSN:
0743-7463
Resumen:
Bimetallic PtSn/C catalysts, prepared on two activated carbon supports of different surface chemistry
by two different preparation procedures, have been analyzed by XAFS spectroscopy. The main goal is to
identify the effect of the support surface oxidation and the preparation procedure (coimpregnation or
successive impregnations) in the interaction of platinum with the support and/or with tin atoms. XAFS
results reveal the effect of the mentioned variables in the structure of the supported phase. It has been
found in dried samples that the interaction of the platinum species with the support is stronger if the
carbon surface is oxidized. The two-step impregnation, compared with the coimpregnation method, renders
samples with a stronger platinum-support interaction. Such an interaction determines the distribution
of the active phase on the support particles. The structure of the metallic phase after reduction is quite
different for samples prepared with the oxidized and nonoxidized carbon support and is also dependent
on the preparation procedure. From the XAFS data, the presence of the following platinum containing
structures is suggested: PtSn alloy, Pt-O-Sn2+ species and pure Pt clusters. The relative proportion of
these structures in the catalysts and their distribution on the support determine the catalytic activity for
cyclohexane dehydrogenation.
these structures in the catalysts and their distribution on the support determine the catalytic activity for
cyclohexane dehydrogenation.
of the active phase on the support particles. The structure of the metallic phase after reduction is quite
different for samples prepared with the oxidized and nonoxidized carbon support and is also dependent
on the preparation procedure. From the XAFS data, the presence of the following platinum containing
structures is suggested: PtSn alloy, Pt-O-Sn2+ species and pure Pt clusters. The relative proportion of
these structures in the catalysts and their distribution on the support determine the catalytic activity for
cyclohexane dehydrogenation.
these structures in the catalysts and their distribution on the support determine the catalytic activity for
cyclohexane dehydrogenation.
-support interaction. Such an interaction determines the distribution
of the active phase on the support particles. The structure of the metallic phase after reduction is quite
different for samples prepared with the oxidized and nonoxidized carbon support and is also dependent
on the preparation procedure. From the XAFS data, the presence of the following platinum containing
structures is suggested: PtSn alloy, Pt-O-Sn2+ species and pure Pt clusters. The relative proportion of
these structures in the catalysts and their distribution on the support determine the catalytic activity for
cyclohexane dehydrogenation.
these structures in the catalysts and their distribution on the support determine the catalytic activity for
cyclohexane dehydrogenation.
-O-Sn2+ species and pure Pt clusters. The relative proportion of
these structures in the catalysts and their distribution on the support determine the catalytic activity for
cyclohexane dehydrogenation.