Electrochemical oxidation in a CH4-H2O system at the interface of a Pt electrode and Y2O3-stabilized ZrO2 electrolyte .1. Determination of the predominant reaction process

In order to elucidate the electrochemical reaction in a CH4-H2O system at the interface of a porous Pt electrode/Y2O3- stabilized ZrO2 electrolyte, measurements were made on the gas composition before and after the reaction under direct-current polarization and on electrochemical impedance spectra at 1073 K. The dominant electrochemical reaction was found to be the redox process of H-2/H2O where H-2 and CO were generated by the steam reforming in a CH4-H2O system. The polarization curves showed good agreement with the model reported by Mizusaki et al. for a H-2-H2O system.