Hydrous ruthenium oxide supported platinum catalysts, i.e., Pt/RuO2 (.) xH(2)O, were synthesized by a feasible solution-phase method. X-ray diffractioti (XRD) and transmission electron microscope (TEM) investigations showed that the uniform Pt nanoparticles were highly dispersed on the support materials. Thermogravimetric analysis (TGA) and differential scanning calorimetry (DSC) analyses revealed that RuO2 (.) xH(2)O has the structure of RuO2 (.) 0.25H(2)O. This support material is believed to be more active than Ru-0 as part of Pt-Ru alloy catalysts. As proved by the cyclic voltammetry (CV) results, the Pt/RuO2 (.) xH(2)O electrode shows higher reactivity towards methanol than that of E-TEK Pt-Ru black electrode. This can be interpreted as that the remarkable boundaries of Pt nanoparticles to RuO2 (.) xH(2)O support provide active sites for complete methanol electro-oxidation. (c) 2005 Published by Elsevier B.V.