Electro-oxidation of methanol and ethanol using a Pt-RuO 2/C composite prepared by the sol-gel technique and supported on boron-doped diamond
A detailed description of the preparation, characterization and electrochemical performance towards methanol and ethanol oxidation in acid medium of a platinum-ruthenium oxide carbon powder composite is presented here. The composite was prepared by the sol-gel technique and fixed on the surface of a boron-doped diamond (BDD) electrode. The physical characterization by XRD and EDX revealed the crystalline nature of the catalysts particles having an average size of 7.2 nm and a mass ratio of practically 1:1 for Pt and Ru, in accordance with the preparation conditions. Initial electrochemical experiments using also glassy carbon as the substrate for the composite showed that BDD has a superior performance, probably related to the very low capacitive currents of that material. The oxidation of methanol and ethanol in H 2SO 4 solutions was studied by cyclic voltammetry, Tafel plots and chronoamperometry and the results were compared to those obtained using a commercial Pt/C powder composite under the same conditions. In all cases, the Pt-RuO 2/C composite showed larger anodic current densities and increased stability than the other material thus confirming the suitability of the simple and straightforward preparation technique for the catalysts.