Pt modified tungsten carbide as anode electrocatalyst for hydrogen oxidation in proton exchange membrane fuel cell: CO tolerance and stability

Pt supported on tungsten carbide-impregnated carbon (Pt/WC/C) is evaluated for hydrogen oxidation reaction in hydrogen/oxygen polymer electrolyte fuel cell at two different temperatures (85 and 105 degrees C), in absence and presence of 100 ppm CO. Carbon supported PtW, prepared by a formic acid reduction method is also evaluated for comparison. At 85 degrees C, the initial hydrogen oxidation activity in the presence of 100 ppm CO is higher for Pt/WC/C, showing a CO induced overpotential of 364 mV for 1 A cm(-2) of current density as compared to an overpotential of 398 mV for PtW/C. As expected, an increase in CO tolerance is observed with the increase in cell temperature for both the catalysts. The increased CO tolerance of Pt/WC/C catalyst is in agreement with CO stripping experiments, for which the CO oxidation potentials occurred at lower potentials at three different temperatures (25,85 and 105 degrees C) in comparison to PtW/C. The stability of both electrocatalysts is evaluated by an accelerated stress test and the results show a better stability for Pt/WC/C catalyst. On the basis of cyclic voltammograms and polarization curves, it is concluded that Pt/WC/C is more stable than PtW/C and can be used as alternative anode catalyst in PEMFC, especially at high temperatures. (C) 2014 Elsevier B.V. All rights reserved.