Self-supported porous heterostructure WC/W[O.sub.3-x] ceramic electrode for hydrogen evolution reaction in acidic and alkaline media

Tungsten carbide (WC)-based materials are widely considered as the hydrogen evolution reaction (HER) process catalysts due to their "Pt-like" electronic structure. Nonetheless, traditional powder electrodes have a high cost, and display problems related to the process itself and the poor stability over operation time. This paper presented a self-supported asymmetric porous ceramic electrode with W[O.sub.3-x] whiskers formed in situ on the walls of the finger-like holes and membrane surface, which was prepared by combining phase inversion tape-casting, pressureless sintering, and thermal treatment in a CO2 atmosphere. The optimized ceramic electrode displayed good catalytic HER activity and outstanding stability at high current densities. More specifically, it demonstrated the lowest overpotentials of 107 and 123 mV and the lowest Tafel slopes of 59.3 and 72.4 mV x [dec.sup.-1] at 10 mA x [cm.sup.-2] in acidic and alkaline media, respectively. This superior performance was ascribed to the structure of the ceramic membrane and the charge transfer efficiency, which was favored by the in situ developed WC/W[O.sub.3-x] heterostructure and the oxygen vacancies. Keywords: hydrogen evolution reaction (HER); porous ceramic membrane; WC/W[O.sub.3-x] heterostructure; self-supported electrode; oxygen vacancies