| Abstract: | In this work the activity of PtMo/C based materials prepared by the formic acid method was evaluated as electrocatalysts for the hydrogen oxidation reaction in the presence of CO, in polymer electrolyte fuel cells. A very high electrocatalytic activity was observed for an anode formed by PtMo/C (60:40) and supplied with H2 containing 100 ppm of CO, which presented an overpotential loss of 100 mV at 1 A cm−2, compared with pure hydrogen. Several electrode configurations based on Mo/C and PtMo/C CO filtering layers, having a Pt-based catalyst layer, were evaluated. In all cases an enhancement of electrocatalytic performance was observed, as compared with the standard Pt/C electrode. It is concluded that the CO tolerance is achieved through an electrochemical surface reaction of adsorbed CO with surface oxides, as proposed by the bifunctional mechanism, acting together with a heterogeneous chemical reaction of CO with water molecules catalyzed by Mo species and resulting in a lowering of the CO concentration in the gas channels of the electrode. |
