Synthesis of tungsten carbide nanocrystals and its electrochemical properties

Tungsten carbide (WC) nanocrystals were prepared by a solvothermal method using Mg as the reductant and WO3 and anhydrous ethanol as the precursors. The effect of time and temperature on the synthesis of WC was investigated and a probable formation mechanism was discussed. The obtained WC crystals were characterized by X-ray diffraction, transmission electron microscopy, energy dispersive spectroscopy, and electrochemical methods. Hexagonal WC was successfully prepared when the temperature was as low as 500 degrees C. The content of carbon was more than that of W and the composition of the treated sample was C and WC only. The diameter of WC nanocrystals was ranged from 40 to 70 nm and the crystal was dispersed on C films. The WC nanocrystals promoted the Pt/C electrocatalyst ability obviously for the oxygen reduction reaction with the onset potential over 173 mV, which was more positive compared with that of the traditional Pt/C electrocatalyst.