An Approach for the Study on Supported Metal Catalysts with Model Catalysts

Abstract

An application of model catalysts has been presented as one of the methods for investigating the catalytic properties of supported metal catalysts. The model catalysts can be prepared in situ by vacuum evaporation onto an amorphous substrate (film of SiO2, Al2O3, or carbon) and studied by such techniques as photoelectron and Auger electron spectroscopy; industrial supported metal catalysts are unsuitable for such techniques using UHV systems. Ensembles prepared in this way offer the possibility of investigating not only the physical properties of particles but also their surface reactivity with simple gases. Apart from the interest in model catalysts, the small metal particles themselves deserve attention; the electronic properties of metal aggregates in size ranges where discrete valence band levels are expected have scarcely been examined. The advantages and application methods of the model catalysts are introduced as well as recent literature on the electronic properties of small metal particles and other approaches for this field.