二氧化硅负载的金-钯模型催化剂的制备与表征

Preparation and characterization of silica supported Au-Pd model catalysts.

作者信息

Luo K, Wei T, Yi C-W, Axnanda S, Goodman D W

机构信息

Department of Chemistry, Texas A&M University, P. O. Box 30012, College Station, Texas 77842-3012, USA.

出版信息

J Phys Chem B. 2005 Dec 15;109(49):23517-22. doi: 10.1021/jp0553131.

DOI:10.1021/jp0553131

PMID:16375326

Abstract

Au-Pd bimetallic model catalysts were synthesized as alloy clusters on SiO2 ultrathin films under ultrahigh vacuum (UHV) conditions. The surface composition and morphology were characterized with low energy ion scattering spectroscopy (LEIS), infrared reflection absorption spectroscopy (IRAS), and temperature programmed desorption (TPD). Relative to the bulk, the surface of the clusters is enriched in Au. With CO as a probe, IRAS and TPD were used to identify isolated Pd sites at the surface of the supported Au-Pd clusters. Ethylene adsorption and dehydrogenation show a clear structure-reactivity correlation with respect to the structure/composition of these Au-Pd model catalysts.

摘要

在超高真空（UHV）条件下，在SiO₂超薄膜上合成了金-钯双金属模型催化剂，其形态为合金团簇。采用低能离子散射光谱（LEIS）、红外反射吸收光谱（IRAS）和程序升温脱附（TPD）对其表面组成和形态进行了表征。相对于体相，团簇表面富含金。以CO为探针，利用IRAS和TPD来识别负载型金-钯团簇表面的孤立钯位点。乙烯吸附和脱氢反应表明，这些金-钯模型催化剂的结构/组成与结构-反应活性之间存在明显的相关性。