H-1-NMR OF HYDROGEN CHEMISORBED ON PT-AU/AL2O3 CATALYSTS - EVIDENCE FOR THE FORMATION OF MIXED PARTICLES

被引:6
作者
ROUABAH, D
FRAISSARD, J
机构
[1] Laboratoire de Chimie des Surfaces, CNRS URA 1428, Université Pierre et Marie Curie, Paris Cedex 05, 75252, case 196
关键词
H-1; NMR; HYDROGEN CHEMISORPTION; PT-AU BIMETALLIC CATALYST; METAL DISPERSION;
D O I
10.1007/BF00806881
中图分类号
O64 [物理化学(理论化学)、化学物理学];
学科分类号
070304 ; 081704 ;
摘要
The evolution of the Pt-Au/Al2O3 system with the reduction time can be followed by (1)HNMR of chemisorbed hydrogen. When the reduction time increases, the signal with the positive shift, due to hydrogen chemisorbed on pure gold, decreases and disappears completely. At the same time there is a large variation in the negative chemical shift of the hydrogen chemisorbed on the particles containing platinum. This evolution of the NMR spectra demonstrates that mixed Pt-Au particles are formed. Although it appears that after a very long reduction time the platinum covers the gold, the distribution of these two metals in the particles at the atomic scale cannot be determined by this technique.
引用
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页码:321 / 329
页数:9
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