FTIR study of the oxidation reaction of CO with O2 over bimetallic Pd-Rh/SiO2 catalysts in an oxidized state

被引:11
作者
Araya, P [1 ]
Weissmann, C [1 ]
机构
[1] Univ Chile, Dept Ingn Quim, Santiago, Chile
关键词
CO oxidation; Rh-Pd; silica; synergism; catalysis;
D O I
10.1023/A:1019014932471
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
CO species adsorbed on the surface of oxidized bimetallic Rh-Pd catalysts, prepared by coimpregnation and sequential impregnation methods, were analyzed in situ by IR spectroscopy, during the reaction of CO with O-2 in an oxidizing atmosphere. The results show that the two methods of impregnation lead to the existence of oxidized Rh on the surface of the bimetallic catalyst, however, in the case of the sequential impregnation method, the Pd surface is more reduced than in the case of catalysts prepared by coimpregnation. The simultaneous presence of reduced Pd and oxidized Rh that occurs in the catalysts prepared by sequential impregnation allows the existence of a synergistic effect similar to that proposed in the literature for the Pt-Rh system. The lower degree of oxidation of the Pd in the catalysts prepared by sequential impregnation, is mainly due to the fact that the Pd in these catalysts comes from the organic precursor palladium acetylacetonate, while in the catalysts prepared by coimpregnation, the Pd comes from the precursor PdCl2.
引用
收藏
页码:33 / 39
页数:7
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