Preparation of Pure Tungsten Carbide and Catalytic Activity of Platinum on a Tungsten Carbide Nanocrystalline Support for Oxygen Reduction

Abstract

Single nanocrystalline tungsten carbide has been firstly synthesized by an intermittent microwave heating (IMH) method at an optimized ratio of tungsten to carbon. The X-ray diffraction (XRD) determination confirmed that the tungsten carbide prepared from a precursor of 30 wt% W and 70 wt%C gives almost pure WC nanocrystal with hexagon-type structure. The Pt nanoparticles supported on single nanocrystalline tungsten carbide (Pt-WC/C) electrocatalysts are prepared by the IMH method. The performance for oxygen reduction on Pt-WC/C is tested in alkaline media. The Pt-WC/C with one third of Pt loadings gives more positive onset potential and higher exchanging current density compared with Pt/C, resulting in a 50 mV overpotential reduction for oxygen reduction reaction.