Methanol Electrooxidation on Pt/RuO<inf>2</inf> Catalyst

Abstract

Abstract: A catalytic coating, composed of a mixture of nanocrystals of Pt and RuO2, used for oxidation of CH3OH, was formed by the thermal procedure. The size of the RuO2 nanocrystals was increasing and of Pt was decreasing with increasing the content of RuO2. The optimal coating composition depended on potential. At more positive potentials, the optimal coatings contained lower amounts of RuO2. The oxidation reaction of CH3OH on the coatings with the RuO2 content higher than optimal, was determined by dehydrogenization of CH3OH. At lower amounts of RuO2, oxidation of CH3OH was determined by the oxidation reaction of intermediates COad with oxy species of ruthenium. The catalytic effect was caused by a bifunctional mechanism. The bifunctional mechanism is based on the fact that oxy species were formed on Ru at more negative potentials than on Pt. These oxy species oxidized COad intermediates, bound to adjacent Pt atoms and thus discharged them for dehydrogenation of the subsequent CH3OH molecules.