EXAFS EVIDENCE OF CARBON MONOXIDE-INDUCED GROWTH OF PD PARTICLES ENCAGED IN ZEOLITE-Y

被引：55

作者：

ZHANG, ZC

CHEN, HY

SHEU, LL

SACHTLER, WMH

机构：

[1] Ipatieff Laboratory, Center for Catalysis and Surface Science, Northwestern University, Evanston

来源：

JOURNAL OF CATALYSIS | 1991年 / 127卷 / 01期

基金：

美国国家科学基金会;

关键词：

D O I：

10.1016/0021-9517(91)90221-O

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：

EXAFS data of Pd in zeolite NaY show that after calcination at 500°C and reduction at 350°C small Pd clusters are formed in the supercages of the zeolite with a compressed PdPd distance of 2.68 Å and an average coordination number of CN = 4, corresponding to nuclearity of 6 Pd atoms. Adsorption of CO results in a significantly increased cluster size and a relaxed PdPd distance of 2.70 Å. The average coordination number of Pd (CN = 6) is consistent with Pd clusters of 13 atoms which are confined in the supercages by the dimension of the windows. The enhanced rate of coalescence due to CO indicates that CO adsorption weakens not only PdPd bonds in the cluster, but also the interaction of the cluster with the zeolite. However, no Pd cluster disintegration by CO adsorption is observed. © 1991.

引用

页码：213 / 220

页数：8

共 45 条

[1] EXTENDED X-RAY-ABSORPTION FINE-STRUCTURE OF SMALL CU AND NI CLUSTERS - BINDING-ENERGY AND BOND-LENGTH CHANGES WITH CLUSTER SIZE [J].