Surface characterization of ruthenium-tin oxide electrodes

The difference of the electrocatalytically active sites of RuO2-SnO2/Ti electrodes among the ruthenium-tin composition were revealed by the electrochemical surface analysis technique. The voltammetric peaks due to the oxidation of Ru6+ to Ru7+ were observed in cyclic voltammograms measured in NaOH. The peaks at higher potential corresponded to oxidation of the ruthenium cations surrounded by ruthenium oxide while those at lower potential corresponded to oxidation of the ruthenium cations surrounded by tin oxide. The electron density of the ruthenium cation would depend on the number of the surrounding tin cations. (C) 1997 Elsevier Science B.V.