【摘要】 由分子筛笼内包容的铂羰基簇合物［Pt（12）（CO）（24）］（2－）／NaY和［Pt9（CO）（18）］（2－）／NaY经还原得到的样品Pt（12）／NaY和Pi9／NaY的分散度用EXAFS和化学吸附进行了表征．对Pt（12）／NaY和Pi9／NaY，EXAFS分析分别给出R（Pt－Pt）＝2．74■，配位数C．N．＝4．2和R（Pt－Pt）＝2．74■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／Al2o3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Pi9／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．更多还原

【Abstract】 The catalysts derived from the reduction of intrazeolite Pt carbonyl clusters [Pt(12)(CO)(24)](2-)/NaY and [Pt9(CO)(18)](2-)/NaY were characterized by EXAFS and chemisorption techniques. EXAFS analysis gave R(Pt-Pt)=2.74, C.N.=4.2 for Pt(12)/NaY and R(Pt-Pt)=2.74, C.N.=3.8 for Pt9/NaY, whil the chemisorption of H2 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 Pt9/NaY respectively. Compared with the results of Pt/Al2O3, it is concluded that highly dispersed Pt/NaY catalysts were derived from the intrazeolie Pt carbonyl clusters. Because of the structureal changes of reduced Pt carbonyl clusters, the recarbonylation of Pt12/NaY and Pt9/NaY can not regenerate the same Pt carbonyl clusters as their precursors.更多还原