TEM observation of the interaction in supported precious metal catalysts
Abstract: The catalyst of Pt/SnO2 was prepared by the impregnation method. The catalytic activities of Pt/SnO2 catalysts pretreated under several conditions were investigated for the combustion of ethyl acetate. The activity was degraded by the heat-treatment in a reducing atmosphere, and was recovered to some extent by the reoxidation treatment. The interface between platinum particles and SnO2 particles were observed by TEM so as to elucidate the cause of the change in catalytic activity. In the Pt/SnO2 catalyst reduced in hydrogen, the particles with core-shell structure were clearly observed. On the other hand, the redispersion of platinum particles was confirmed in the reoxidized Pt/SnO2 catalyst. Thus, it was verified that the catalytic activities of Pt/SnO2 were strongly related with their nano structure. The analogous structural change proceeded in the other precious metal catalysts such as Ru/SnO2, Pd/SnO2, and Rh/SnO2.
Key words: Supported precious metal catalyst, Strong interaction, Combustion catalyst, Pt/SnO2, Transmission electron microscopy (TEM)