Three-dimensional macroporous W2C inverse opal arrays for the efficient hydrogen evolution reaction

Abstract

The development of a low-cost and durable non-precious metal-based electrocatalyst for the hydrogen evolution reaction (HER) is important to realize highly efficient overall water splitting. Here, we report the design and fabrication of a binder-free electrocatalyst of three-dimensional macroporous ditungsten carbide (W₂C) inverse opal (W₂C IO) arrays by a facile thermal carburization process with WO₃ IO as a template. The as-fabricated W₂C IO exhibits superior electrocatalytic performance in 0.5 M H₂SO₄ solution in terms of a low overpotential of 146 mV to reach a current density of 10 mA cm⁻², a low Tafel slope of 78 mV dec⁻¹ and excellent long-term stability. The superior performance can be attributed to the favorable electronic structure and hydrogen adsorption Gibbs free energy of W₂C evidenced by theory calculations and the enhancement of the charge/mass transfer process by the 3D macroporous arrayed electrode design.