Evaluation of Catalytic Activity of Pt and Pt-Ru Catalysts for Electro-oxidation of Methanol in Acid Medium by Cyclic Voltammetry

Abstract

The cyclic voltammetric study on the electro-oxidation of methanol on 30 % Pt and 20 % Pt +10 % Ru catalysts supported on Vulcan XC-72 was carried out in 0.5 M H 2 SO 4 . Kinetic parameters such as exchange current density, Tafel slope and heterogeneous rate constants were calculated. The 30 % Pt showed a higher apparent catalytic activity for the electro-oxidation of methanol as compared with 20 % Pt + 10 % Ru catalyst. The presence of Ru did not contribute significantly towards the apparent catalytic activity of a catalyst for the electro-oxidation of methanol but it may be useful to prevent the catalyst from CO poisoning. Thermodynamic parameters, H * , S * , and G 298 * have been evaluated. The values of H * and G 298 * were positive showing that the electrooxidation of methanol is an endothermic and non-spontaneous process.