Nearly hollow Ru–Cu–MoO2 octahedrons consisting of clusters and nanocrystals for high efficiency hydrogen evolution reaction

Abstract

Regular hollow catalysts have aroused increasing attention in electrocatalysis owing to large surface area, many more active centers and fast mass transfer. Nevertheless, the structure regulation of regular hollow catalysts, especially octahedrons, is scarcely reported. Herein, by developing a facile strategy, we successfully integrate Ru clusters and Cu–MoO₂ nanocrystals into a fused nearly hollow Ru–Cu–MoO₂ octahedron encapsulated in carbon. Due to the synergic effect and the advantageous structure and composition, such a multiple-nanocomponent catalyst merely requires 22 and 48 mV overpotentials at a current density of 10 mA cm⁻² for the hydrogen evolution reaction (HER) in 1 M KOH and 0.5 M H₂SO₄ solutions, respectively. More importantly, in alkaline seawater, nearly hollow Ru–Cu–MoO₂ octahedrons also present remarkable HER activity (23 mV @ 10 mA cm⁻²), indicating potential applications in hydrogen production from seawater electrolysis. Furthermore, density functional theory (DFT) calculation results unveil that the excellent catalytic activity of Ru–Cu–MoO₂ is on account of its relatively low hydrogen adsorption Gibbs free energy (ΔG_H*) and water adsorption energy. The present work provides a new approach for designing advanced Ru-based catalysts for the HER and beyond.