Methanol Oxidation on Ru-Modified Preferentially Oriented Pt Electrodes in Acidic Medium

Abstract

Polycrystalline Pt electrodes have been faceted by fast periodic potential scans. The electrocatalytic behavior of preferentially oriented "Pt(111)", "Pt(110)", and "Pt(100)" surfaces modified by Ru submonolayers was examined by cyclic voltammetry and chronoamperometry. The enhancement factor for methanol electro-oxidation depends on the surface crystallography and on the Ru coverage. The optimum Ru coverage at room temperature was found to be 30-40% of a monolayer for all electrodes under study. The catalytic activity of the Ru/"Pt(hkl)", electrodes for methanol oxidation was compared with that of Ru/Pt(111). The catalytic activity at optimum Ru coverage decreases in the following order: "Pt(111)" > "Pt(110)" > Pt(111) > "Pt(100)". The reactivity of the Ru/"Pt(hkl)" electrodes for methanol oxidation can be attributed to the high number of steps and defect sites on their surfaces. © 2004 The Electrochemical Society. All rights reserved.