物理化学学报 >> 1994, Vol. 10 >> Issue (06): 549-554.doi: 10.3866/PKU.WHXB19940613

研究论文 上一篇    下一篇

由分子筛笼内铂羰基簇合物得到的催化剂的分散度研究

李光进, 杨亚书, 郭燮贤, 市川胜   

  1. 中国科学院大连化学物理研究所催化基础国家重点实验室,大连 116023|日本北海道大学触媒化学研究所,札幌 060 日本
  • 收稿日期:1992-12-12 修回日期:1993-09-20 发布日期:1994-06-15
  • 通讯作者: 李光进

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

摘要:

由分子筛笼内包容的铂羰基簇合物[Pt_(12)(CO)_(24)]~(2-)/NaY和[Pt_9(CO)_(18)]~(2-)/NaY经还原得到的样品Pt_(12)/NaY和Pi_9/NaY的分散度用EXAFS和化学吸附进行了表征.对Pt_(12)/NaY和Pi_9/NaY,EXAFS分析分别给出R_(Pt-Pt)=0.274 nm,配位数C.N.=0.42和R_(Pt-Pt)=0.274 nm配位数C.N.=3.8,而化学吸附结果分别为H/Pt=1.26,CO/Pt=0.69和H/Pt=1.24,CO/Pt=0.64.与浸渍法制备的Pt/Al_2O_3相比小得多的Pt-Pt配位数及大的化学吸附值说明,由分子筛笼内铂羰基簇合物出发,我们得到了高分散的Pt/NaY催化剂.由于还原后原子堆积形式的变化,Pt_(12)/NaY和Pt_9/NaY的再还原羰基化不能可逆地得到与前驱体相同的铂羰基簇合物.

关键词: 分子筛, 铂, 羰基簇合物, 分散度

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