Synergistic effect of Ru nanoclusters on WC1−x anchored on N-doped carbon nanosheets to promote highly efficient alkaline hydrogen evolution

Abstract

Developing novel non-noble electrocatalysts with high efficiency and low cost for the alkaline hydrogen evolution reaction (HER) remains a great challenge. Although tungsten carbides with a Pt-like electronic structure have been considered as promising candidates to replace noble metal electrocatalysts, their alkaline HER performance is seriously restricted by the sluggish kinetics of water dissociation, the difficulty of hydrogen desorption and low conductivity. Herein, Ru nanocluster-anchored WC_1−x nanoparticles supported on a porous N-doped carbon nanosheet (Ru/WC_1−x@NC) hybrid was successfully prepared through a facile pyrolysis of a mixture of WO₃, RuCl₃ and molten urea. The Ru nanoclusters significantly promote the dissociation of water molecules, and the synergistic effect between the Ru nanoclusters and WC_1−x nanoparticles and the strong coupling between the N-doped carbon substrate and WC_1−x nanoparticles greatly facilitate the reaction kinetics for the alkaline HER. Therefore, the resulting Ru/WC_1−x@NC hybrid displays outstanding catalytic activity with a very low overpotential of 24 mV at 10 mA cm⁻² and a small Tafel slope of 45 mV dec⁻¹ in 1 M KOH, and shows excellent long-term durability for the HER. This work sheds light on a feasible strategy by which to develop low-cost electrocatalysts with high efficiency and stability towards the alkaline HER via composition and nanostructure engineering modulation.