Design of metal-substituted tungsten diboride as an efficient bifunctional electrocatalyst for hydrogen and oxygen evolution

Abstract

Transition metal diborides (TMDbs) have recently attracted the scientific community's attention because of their remarkable attributes as bifunctional catalysts for both oxygen and hydrogen evolution reactions (OER/HER). Herein, we present the electrocatalytic OER/HER of Co- and Ni-incorporated WB2 (W(1-x)TMxB2: TM = Ni and Co; x = 0, 0.1, 0.2, and 0.3) under alkaline media. Metal-substituted WB2 was constructed with two different synthetic approaches, molten salt (ms) and carbothermal (ct) reduction, to explore the influence of morphology on electrochemical properties to drive OER/HER in 1 M KOH. In general, materials synthesized by the ms technique are relatively better catalysts toward OER/HER. Among the samples, W0.8Co0.2B2/ms demanded the lowest respective overpotential of 340 and 363 mV to generate the current density of 10 mA cm(-2) for OER/HER and exhibited favorable stability at 10 mA cm(-2) for 12 h which were ascribed to high double-layer capacitance (0.247 mF cm(-2)) and low charge-transfer resistance.