Tungsten boride: a 2D multiple Dirac semimetal for the hydrogen evolution reaction

Abstract

Development of a non-noble-metal hydrogen-producing catalyst plays a central role in clean energy conversion, enabling a number of sustainable processes for future technologies. Here we propose a two-dimensional (2D) tungsten boride (WB₄) lattice, with the Gibbs free energy for the adsorption of atomic hydrogen (ΔG_H) tending to the ideal value (0 eV) at the 3% strained state, leading to better hydrogen evolution reaction (HER) activity. Based on first-principles calculations, we present a systematic theoretical study for the WB₄ lattice with special emphasis on the configuration design and electronic structure, and find that the WB₄ lattice has multiple Dirac cones around the Fermi level with considerable Fermi velocities to transfer electrons in all directions throughout its structure. Importantly, together with the d-orbital of W, the p-orbitals of borophene subunits in the WB₄ lattice can modulate the d band centre to achieve good HER performance. Our research provides a guiding principle for designing and regulating 2D catalysts from the emerging field of noble-metal-free lattices.