High-efficiency Co6W6C catalyst with three-dimensional ginger-like morphology for promoting the hydrogen and oxygen evolution reactions

Development of electrocatalysts composed of low cost and abundant elements that exhibit catalytic activity comparable to noble metals is important for water splitting. As such, in this study, a catalyst material with a ginger-like morphology consisting of Co6W6C is synthesized via a hydrothermal reaction and pyrolysis treatment. The Co6W6C catalyst exhibits satisfactory electrochemical properties towards both hydrogen and oxygen evolution reactions in an alkaline electrolyte, with a low overpotential, low Tafel slope, and durable stability. Co6W6C possesses a high activity for the hydrogen evolution reaction in alkaline conditions, with an onset potential and overpotential of -0.024 V and 101 mV, respectively, and low Tafel slope of 80.5 mV dec(-1) at a current density of 10 mA cm(-2). In addition, Co6W6C achieves a current density of 10 mA cm(-2) for the oxygen evolution reaction at an overpotential of only 343 mV. Furthermore, electrochemical stability tests indicate that the Co6W6C catalyst maintains 91% of the original current after 60,000 s for the hydrogen evolution reaction and 95% of the original current after 45,000 s for the oxygen evolution reaction. Moreover, electrochemical splitting of water via a two-electrode system employing this catalyst can hold 89% of the initial current after 40,000 sin 1 M KOH. (C) 2019 Hydrogen Energy Publications LLC. Published by Elsevier Ltd. All rights reserved.