CO and CO/H_2 electrooxidation on carbon supported Pt-Ru catalyst in phosphotungstic acid (H_3PW_(12)O_(40)) electrolyte

摘要

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 activation energy of about 50 kJ mol~(-1) was found for CO oxidation at 0.6 V vs NHE. Fractional reaction orders close to 0.5 and -0.4 with respect to carbon monoxide and proton concentration, respectively, were observed. Tafel slopes were close to 136 mV dec~(-1) at 70 ℃ for both CO and CO/H_2 oxidation. The PWA elecrtrolyte appeared to promote the methanol electrooxidation by increasing the rate of water discharge at the electrode.