Oxygen reduction at the Ag|Gd₀.₂Ce₀.₈O₁.₉ interface studied by electrochemical impedance spectroscopy and cyclic voltammetry at the silver point electrode
By M. Mosialek,P. Nowaka, M. Dudek, G. Mordarski
Published in Electrochimica Acta
2014
Abstract
Reduction of oxygen at the silver point electrode|Gd₀.₂Ce₀.₈O₁.₉ interface was studied by cyclic voltammetry and electrochemical impedance spectroscopy. Measurements were performed in the 500–700 °C temperature range, at the atmospheric pressure, in oxygen and in argon/oxygen atmospheres. The results of the experiments are consistent with the mechanism in which the oxygen reduction reaction proceeds through the non-electrochemical adsorption/dissociation step and a two-electron two-step electrochemical reaction with the transfer of the first electron as a rate-determining step. Slow diffusion of oxygen is confirmed by both electrochemical impedance spectroscopy and cyclic voltammetry techniques. New equivalent electrical circuit for the investigated interface is proposed.