Pt-Ru/C, Pt-Dy and Pt-Ru-Mo/C electrocatalysts prepared by Bönnemann´s method have been studied as porous thin films on high surface area carbon electrodes, in order to evaluate their electroactivity on CO desorption in PEM fuel cells. For comparison electrode precursor powders with and without thermal treatment were considered. Cyclic voltammetry showed that addition of Mo in the well-established Pt/Ru system is very promising for methanol oxidation. In order to compare the electroactivity of different catalysts a normalization procedure based on the amount of Pt was used.

Novas formulações de eletrocatalisadores ternários do tipo Pt/Ru/Mo foram desenvolvidas pelo método de Bönnemann e caracterizadas pelas técnicas de análise por energia dispersiva de raios X (EDX), difração de raios X (XRD), voltametria cíclica (CV) e curvas de polarização (E vs. i), para a oxidação de H2 , mistura H2/CO e metanol em células a combustível tipo PEMFC. A estrutura dos catalisadores obtida é formada por nanocristais altamente dispersos na matriz de carbono, com 2 nm de tamanho médio da nanopartícula. Os resultados da voltametria cíclica sugerem um aumento considerável da eletroatividade do catalisador com a adição de cocatalisadores. A análise das curvas de polarização sugere que o catalisador ternário Pt/Ru/Mo pode ser interessante do ponto de vista tecnológico.

The synthesis of ternary electrocatalysts Pt/Ru/Mo type were performed according to the Bönnemann method and characterized by the following techniques: energy dispersive analysis (EDX), X-rays diffraction (XRD), cyclic voltammetry (CV) and polarization curves (E vs. i) for the oxidation of H2, H2/CO and methanol in a Proton Exchange Membrane Fuel Cell (PEMFC). Catalysts structure consists of highly dispersed nanocrystals in carbon support, with an average particle size of 2 nm. The results of cyclic voltammetry suggest an enhancement of the catalyst electroactivity with the addition of cocatalysts. Polarization curves indicate that Pt/Ru/Mo systems could be employed as electrode material for PEM fuel cell for technological application.