Investigation of the oxygen reduction reaction on Pt-WC/C electrocatalysts in alkaline media

The activity of Pt catalysts dispersed on tungsten carbide (WC) prepared with a high surface area carbon with two different WC/C ratios is investigated for the oxygen reduction reaction (ORR) in alkaline electrolyte. The electrochemical methods employed are cyclic voltammetry (CV) and steady-state polarization carried out on an ultrathin catalyst layer deposited on the disk of a rotating ring-disk electrode. The PtWC-based catalysts show higher activity for the ORR compared to Pt/C, also involving a transfer of 4 electrons per oxygen molecule. CV and X-ray absorption near edge structure spectroscopy (XANES) results for the PtWC-based materials indicate weaker Pt-OHx interaction in these materials, resulting in a lower Pt-oxide coverage and explaining the increased rate of the ORR, as compared to Pt/C.