Ordered mesoporous tungsten carbide nanoplates as non-Pt catalysts for oxygen reduction reaction

Abstract

We represent well-defined mesoporous tungsten carbide catalysts for oxygen reduction reaction in alkaline solution. The pore structures of tungsten carbide nanoplates (WC-700-m, WC-800-m and WC-900-m) are formed as a function of reaction temperature of 700, 800 and 900°C in CH4(25%)/H2(75%) atmosphere for 9h using layered tungsten nitride nanoparticles. All the tungsten carbide nanoplates exhibit isothermal sorption characteristics of mesoporous structure and fairly monomodal pore size distribution in the range of 6.6–7.2nm. The WC-700-m, WC-800-m, and WC-900-m exhibit X-ray diffraction patterns corresponding to WC1−x, WC1−x+WC, and WC phase, respectively. In particular, the WC-900-m shows highly improved electrocatalytic activity toward oxygen reduction reaction in an alkaline solution as compared to the WC-900-c. Furthermore, the WC-900-m supported Pd catalyst as a non-Pt exhibits much enhanced electrochemical oxygen reduction properties in comparison with conventional Pt catalyst.