Dual-site synergistic catalysis of a single atomic Ru and tungsten compound heterojunction for enhanced alkaline hydrogen evolution

Abstract

It is important to develop efficient, low-cost alkaline electrolytic water catalysts to replace the commercial Pt/C catalysts to promote the hydrogen economy. This work presents a dual-site synergistic catalyst (Ru-W₂N/WO₂) designed using a single-atommodified heterojunction strategy. This strategy simultaneously optimizes the kinetics of water dissociation and hydrogen adsorption, achieving catalytic activity and stability that exceed those of Pt/C. When applied as a cathode in membrane electrode assembly devices, the modified catalyst Ru-W₂N/WO₂ exhibits significantly enhanced performance compared to W₂N/WO₂, and it stably operates at a high current density of 100 mA cm⁻² for 270 hours. Through a combination of experimental characterizations and theoretical calculations, the synergistic mechanism of the catalyst is revealed: the W site efficiently adsorbs OH⁻ by virtue of its abundant outermost vacant orbitals. This accelerates water dissociation and hydrogen adsorption, thereby continuously supplying the protons required for the reaction. Meanwhile, the Ru site optimizes the adsorption and recombination of *H and promotes H₂ generation. This study elucidates the dual-site synergistic mechanism of the W heterojunction substrate and Ru single atoms, providing an in-depth understanding on the rational design of efficient alkaline water electrolysis catalysts.