Novel combustion-carbonization preparation of mesoporous tungsten carbide as a highly active catalyst for oxygen reduction
Tungsten carbide (WC) powder was synthesized by a novel combustion-carbonization method. Structure and morphology of WC powder was characterized by X-ray diffraction (XRD), field emission scanning electron microscope (FESEM), transmission electron microscope (TEM) and X-ray photoelectron spectroscopy (XPS). The results show that pure phase of WC powder can be obtained at 850 ℃, the particle size of WC powders is about 30-100 nm. Compared with the conventional calcination-carbonization method, the combustion-carbonization method can obtain WC powders with larger surface area and carbon coating structure. The results of cyclic voltammetry (CV) and linear sweep voltammetry (LSV) measurement provide that WC catalyst exhibits a defined ORR activity in a alkaline solution and its oxygen reduction peak potential, peak current density, and half-wave potential are -0.36 V, 0.5 mA, and -0.31 V, respectively. The preceding test results proved that the WC prepared by this facile method has excellent oxygen reduction catalytic activity.