Acta Phys. -Chim. Sin. ›› 1994, Vol. 10 ›› Issue (06): 549-554.doi: 10.3866/PKU.WHXB19940613

• ARTICLE • Previous Articles     Next Articles

Dispersion of Catalysts Derived from Intrazeolite Pt Carbonyl Clusters

Li Guang-Jin, Yang Ya-Shu, Guo Xie-Xian, Ichikawa Masaru   

  1. State Key Laboratory of Catalysis, Dalian Institute of Chemical Physics, Chinese Academy of Sciences, Dalian 116023| Catalysis Research Center, Hokkaido University, Sapporo 060 Japan
  • Received:1992-12-12 Revised:1993-09-20 Published:1994-06-15
  • Contact: Li Guang-Jin

Abstract:

The catalysts derived from the reduction of intrazeolite Pt carbonyl clusters [Pt_(12)(CO)_(24)]~(2-)/NaY and [Pt_9(CO)_(18)]~(2-)/NaY were characterized by EXAFS and chemisorption techniques. EXAFS analysis gave R_(Pt-Pt)=0.274 nm, C.N.=4.2 for Pt_(12)/NaY and R_(Pt-Pt)=0.274 nm, C.N.=3.8 for Pt_9/NaY, whil the chemisorption of H_2 and CO gave H/Pt=1.26, CO/Pt=0.69 and H/Pt=1.24, CO/Pt=0.64 for Pt_(12)/NaY and Pt_9/NaY respectively. Compared with the results of Pt/Al_2O_3, it is concluded that highly dispersed Pt/NaY catalysts were derived from the intrazeolite Pt carbonyl clusters. Because of the structureal changes of reduced Pt carbonyl clusters, the recarbonylation of Pt_(12)/NaY and Pt_9/NaY can not regenerate the same Pt carbonyl clusters as their precursors.

Key words: Zeolites, Pt, Carbonyl clusters, Dispersion