Jk. Hong et al., ELECTROCHEMICAL OXIDATION OF METHANOL OVER A SILVER ELECTRODE DEPOSITED ON YTTRIA-STABILIZED ZIRCONIA ELECTROLYTE, Journal of catalysis, 163(1), 1996, pp. 95-105
A solid electrolyte catalytic reactor was used to investigate the chan
ge in catalytic activity of the electrode upon conduction of O2- ions
through the electrolyte, The reactor consisted of an yttria-stabilized
zirconia electrolyte disk on which a thin him of the Ag electrode was
deposited, As the catalyst potential was applied below the open circu
it potential or, equivalently, as O2- ions were electrochemically remo
ved from the Ag catalyst electrode to the counter electrode through th
e solid electrolyte, its influence on the O-2 exchange reaction in He-
O-2 flow and CH3OH oxidation to HCHO and CO2 in He-O-2-CH3OH flow was
investigated, It was found from the O-2 exchange reaction study that s
low diffusion of adsorbed oxygen to the catalyst-electrolyte-gas three
-phase boundary, where charge transfer took place, caused a limiting c
urrent, In CH3OH oxidation, a lowered open circuit potential was obser
ved when CH3OH was added to the He-O-2 how Lowering the catalyst poten
tial below this new open circuit potential was found to cause a revers
ible, somewhat nonfaradaic increase in the rate of CO2 formation, but
had little effect on the rate of HCHO formation. Based on the rate equ
ations, this behavior was interpreted in terms of an activated surface
reaction between adsorbed species due to the change in the catalyst w
ork function with changing catalyst potential. (C) 1996 Academic Press
, Inc.