Methanol oxidation on Ru/Pd(poly) in alkaline solution

Polycrystalline Pd electrode, Pd(poly), is modified by Ru nanoislands using spontaneous deposition method. Coverage of Pd(poly) electrode with the deposited Ru are approx. 20, 30 and 50% as estimated from phase atomic force microscopy images. The oxidation state of Pd substrate and the deposited Ru is determined by X-ray spectroscopy (XPS). Electrocatalytic activity of obtained Ru/Pd(poly) bimetallic electrodes is tested towards methanol oxidation in alkaline medium. Cyclic voltammetry and chronoamperometry experiments show the enhanced activity of Ru/Pd(poly) electrodes towards methanol electrooxidation with respect to bare Pd(poly). This is explained by the presence of Ru islands, which provided RuOH and Pd-RuOH sites, necessary for the oxidation of CO as the main intermediate during the oxidation of methanol at lower potentials. 30% Ru/Pd(poly) is the most active of all examined electrodes.