Electro-reduction of oxygen and electro-oxidation of methanol at Pd monolayer-modified macroporous Pt electrode

Abstract

With polystyrene latex spheres self-assembled on indium tin oxide-coated glass electrode as templates, highly ordered macroporous Pt was prepared by electrochemical deposition. Then, the macroporous Pt was modified by Pd monolayer involving the galvanic displacement of Cu monolayer formed by under-potential deposition on macroporous Pt. Electrocatalytic properties of the Pd-modified macroporous Pt electrode for oxygen reduction were investigated by cyclic voltammetry and chronoamperometry in O2-saturated solution containing 0.1 M HClO4. Methanol electro-oxidation on the Pd-modified macroporous Pt surfaces in 0.5 M H2SO4 containing 1 M CH3OH was studied by cyclic voltammetry. The corresponding results showed that Pd-modified macroporous Pt electrode had negative catalytic activity for methanol oxidation in compared with macroporous Pt. However, Pd-modified macroporous Pt electrode had positive electrocatalytic activity to O2 reduction.