DIFFERENT EFFECTS OF RAYLEIGH-TYPE SURFACE ACOUSTIC-WAVES ON CATALYTIC ACTIVITY OF A THIN CU FILM FOR ETHANOL OXIDATION

A surface acoustic wave (SAW) of the Rayleigh-type caused changes in the catalytic activity of a thin Cu film deposited on the SAW propagation path. For ethanol oxidation below 393 K. the catalytic activity increased considerably with SAW on, and the activation energy of the reaction decreased from 5 7 to 37 kJ mol-1. For the reaction at 403 K, however, the SAW decreased the activity to less than one half. The anomalous behavior at higher temperatures is associated with the formation of a Cu oxide phase during the reaction. These results indicate that the SAW effects are strongly dependent on the surface states of the catalyst.