Anomalous enhancement of catalytic activity over a Pd thin film by the effects of resonance oscillation generated on a ferroelectric substrate

A poled ferroelectric lithium niobate single crystal (z-cut) was employed as a substrate, on the planes of which either a catalytically active Pd or an inactive Al metal was deposited at a thickness of 100 nm. Resonance characteristics were measured, and the effects of resonance oscillation on the catalytic activity for ethanol oxidation were examined. For the Al metal, a negligibly small enhancement of the activity occurred at 343 K, whereas, for the Pd metal, the activity increased dramatically with increasing power at a resonance frequency of 3.4 MHz and amounted to 1880 times larger activity at 3 W. The activation energy of the reaction decreased from 156 to 12 kJ mol−1 with power-on. No activity increase was observed at non-resonance frequency. The effects of resonance oscillation on catalytic activity are discussed.