AVS 47th International Symposium
    Surface Science Tuesday Sessions
       Session SS1-TuA

Paper SS1-TuA3
Artificial Control of Catalytic Functions for Reaction Selectivity by Thickness-extensional Mode Resonance Oscillation of Acoustic Wave

Tuesday, October 3, 2000, 2:40 pm, Room 208

Session: Mechanisms and Control of Surface Reactions
Presenter: Y. Inoue, Nagaoka University of Technology, Japan
Authors: Y. Inoue, Nagaoka University of Technology, Japan
Y. Yukawa, Nagaoka University of Technology, Japan
N. Saito, Nagaoka University of Technology, Japan
H. Nishiyama, Nagaoka University of Technology, Japan
Correspondent: Click to Email
Thickness-extensional mode resonance oscillation (TERO) of bulk acoustic waves generated by a piezoelectric effect was applied to a 100 nm Ag or Pd film catalyst deposited on a positively polarized ferroelectric single crystal of z-cut LiNbO3 (z-LN), and the TERO effects on reaction selectivity of the catalyst surfaces were studied. For ethanol decomposition on Ag and Pd, TERO with a resonance frequency of 3.5MHz caused remarkable increases in ethylene production without changing acetaldehyde production. The increased activity decreased to an original low level with turning TERO off. Increases in selectivity for ethylene production with TERO were from 56 to 86% for Ag and 31 to 97% for Pd. The activation energy of ethylene production was lowered significantly by the TERO. For comparison, x-cut LiNbO3 (x-LN) having thickness-shear mode resonance oscillation (TSRO) was employed as a ferroelectric substrate, for which no significant activity enhancements for both ethylene and acetaldehyde production were observed with the resonance oscillation. Laser Doppler measurements showed that TERO caused large dynamic lattice displacement vertical to the surface. The surface potential and photoelectron emission behavior varied with the TERO. TERO has been shown to have influences on the work function of the catalyst surfaces, which permits to change the catalytic functions with selectivity.