CO and CO/H-2 electrooxidation on carbon supported Pt-Ru catalyst in phosphotungstic acid (H3PW12O40) electrolyte

An electrode-kinetic study of the oxidation of CO and CO/H-2 mixtures on a Pt-Ru/C catalyst was carried out in phosphotungstic acid (PWA) electrolyte. The influence of temperature, CO partial pressure and proton concentration on the electrochemical oxidation rate was investigated, An apparent activa tion energy of about 50 kJ mol(-1) was found for CO oxidation at 0.6 V vs N HE. Fractional reaction orders close to 0.5 and -0.4 with respect to carbon monoxide and proton concentration, respectively, were observed, Tafel slop es were close to 136 mV dec(-1) at 70 degrees C for both CO and CO/H-2 oxid ation. The PWA electrolyte appeared to promote the methanol electrooxidatio n by increasing the rate of water discharge at the electrode.