Electrochemically promoted catalysis: The case of ethanol oxidation over Pt

Abstract

Ethanol oxidation was investigated over polycrystalline Pt films deposited on 8 mol% Y2O3-stabilized-ZrO2 (YSZ) in the temperature range of 300-350degreesC. It was found that electrochemical supply of oxygen anions (O2-) to the Pt catalyst results in significant changes both in the rate of ethanol consumption and in the yield of acetaldehyde. Electrochemical supply of O2- anions induces an enhancement of the reaction rate that was found typically 10(3)-10(4) times larger than the Faradaic rate of O2- supply and an almost seven-fold increase in the reaction yield to acetaldehyde. In the range of the applied currents, it was found that the catalytic activation energies of ethanol consumption and acetaldehyde formation can be lowered by 70 and 80%, respectively, with respect to the regular (open-circuit) values. The observed behavior is discussed and explained on the basis of the theory of NEMCA. (C) 2002 Elsevier Science (USA).