Synergistic tailoring of doping and vacancies in tungsten carbide for efficient hydrogen evolution

Abstract

Hydrogen has been considered as a promising candidate to replace fossil fuel with the development of fuel cells and hydrogen internal combustion engines. Tungsten carbide (WC) is considered as an alternative to noble-metal catalysts for the hydrogen evolution reaction (HER) due to its unique platinum-like electronic properties. However, the high catalytic activity of WC is hampered by the strong binding with hydrogen. Herein, a synergy strategy of dopants and vacancies for WC is proposed for promoting hydrogen evolution in acidic and alkaline solutions. Carbon vacancies are introduced with the introduction of Zn atoms. The as-obtained V_C-Zn-WC catalyst is composed of uniform spherical nanoparticles with an average particle size of 3 nm, which can efficiently increase the specific surface areas and further expose more active centers. The V_C-Zn-WC catalyst shows superior stability and high catalytic activity with low overpotentials of −187 and −229 mV at the current density of −10 mA cm⁻² in 1 M KOH and 0.5 M H₂SO₄, respectively. Density functional theory calculations and experimental results demonstrated that such a strategy of dopant and vacancy synergy can significantly optimize the electronic structure of WC and thus improve its HER activity. This work provides a feasible method for the design of transition metal carbides to promote their HER performance.