A Novel Carbon-Encapsulated Cobalt-Tungsten Carbide as Electrocatalyst for Oxygen Reduction Reaction in Alkaline Media

Carbon-encapsulated cobalt-tungsten carbides (CoWC@C) were synthesized by reduction and carbonization method and used as the electrocatalyst for oxygen reduction reaction (ORR) in direct methanol fuel cells. The as-prepared samples were characterized by transmission electron microscope, X-ray diffraction, and X-ray photoelectron spectroscopy. The results show that CoWC@C consists of outer layer carbon and internal Co3W3C, WC, and Co. The cyclic voltammetry results show that CoWC@C has high ORR activity, long-term durability, and good methanol-tolerant performance. It is revealed that the main active phase for ORR of CoWC@C is Co3W3C, and the outer layer carbon plays the role in improving the durability of the catalyst.