INFLUENCE OF ALUMINA SURFACE-STRUCTURE ON GROWTH AND ADSORPTION PROPERTIES OF PD PARTICLES

The partial CO dissociation observed on small Pd particles deposited o n gamma-alumina and only molecular adsorption of CO on Pd/(0001) alpha -alumina model catalysts show that the surface structure of alumina ca n influence the reactivity of supported clusters. To understand the ef fect of metal-support interaction, Pd particles were deposited on alum ina substrates of different surface structure [(0001), (1-102)]. The s urface of alumina substrates was investigated by means of reflection h igh energy electron diffraction (RHEED). The growth of Pd particles, t heir structure and orientation were observed by RHEED. In order to com pare the catalytic properties of supported Pd particles, the study of CO and O adsorption was performed by temperature-programmed desorption (TPD) using molecular beam techniques.