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 (ΔGH) 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.