Performance of Ru-, Sn- and Co-promoted Pt/C catalysts for electrocatalytic oxidation of methanol

Carbon-supported Pt-M (M=Ru, Sn, and Co) catalyst samples were prepared by the colloidal method and characterized by X-ray diffraction and energy dispersive X-ray spectroscopy. The results indicated that the Pt-M alloy particles distributed homogeneously on the carbon, the particle size was 2-6 mn, and the proportion of the metal element in the alloy particles coincided with that in the precursor. Cyclic voltammetry was carried out to measure the catalyst activity in different alkaline concentration electrolytes. The onset potential and spike potential for electrocatalytic oxidation of methanol changed and the peak currents increased with the increase in the alkali concentration. The catalyst activity decreased in the order Pt50Ru50/C>Pt50Sn50/C> Pt75Co25/C. The activity of Pt/C was enhanced markedly after adding Ru, and the peak current of Pt50Ru50/C reached 634. 7 mA/mg in the solution of 1.0 mol /L NaOH + 1.0 mol /L CH3OH at 25 degrees C.