XAFS study of tin modification of supported palladium catalyst for 1,3-butadiene hydrogenation in the presence of 1-butene

被引:41
作者
Choi, SH [1 ]
Lee, JS [1 ]
机构
[1] Pohang Univ Sci & Technol, Dept Chem Engn, Pohang 790784, South Korea
关键词
XAFS; 1,3-butadiene hydrogenation; Pd catalyst; tin modification;
D O I
10.1006/jcat.2000.2893
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
Alumina-supported palladium catalyst, which is active for the hydrogenation of 1,3-butadiene, was modified by tin using various tin precursors. The structure of modified catalysts was studied by XAFS and TPR. Before modification, palladium on alumina existed in an electron-deficient hydride state, which was revealed by a shift to a higher Pd K-edge energy in XANES and by an increased Pd-Pd distance in EXAFS fitting. However, tin modification caused the palladium edge energy to decrease to the value of zero valent palladium metal and destroyed the Pd ensembles by making Pd-Sn bonds, irrespective of the nature of tin precursor. This was responsible for the increased 1-butene selectivity in the hydrogenation of 1,3-butadiene in the presence of 1-butene. A carbonaceous species was formed in the catalyst modified with an organic tin precursor, while the inorganic tin modification produced a tin oxide-like species in addition to the formation of Sn-Pd bonds. (C) 2000 Academic Press.
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页码:176 / 185
页数:10
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