Surface-oxidized RuCu single-atom alloy enables accelerated alkaline hydrogen evolution through tuned OH adsorption

Surface-oxidized RuCu single-atom alloy synthesized via PLIL. • Ultrafine ~3 nm particles with atomically dispersed Cu and surface oxide. • Downshifted d-band center weakens *OH adsorption and optimizes ΔG H . • Superior alkaline HER: 27.5 mV@10 mA cm −2 , Tafel 24.2 mV dec −1 . • Synergistic Cu and surface oxidation modulation enhances water dissociation. Hydrogen evolution reaction (HER) in alkaline media is severely hindered by sluggish water dissociation kinetics and the strong adsorption of hydroxyl intermediates (*OH). Herein, we report a surface-oxidized RuCu single-atom alloy (RuCuO) supported on carbon nanotubes, synthesized via a pulsed laser irradiation in liquids (PLIL) strategy. The resulting catalyst features ultrafine nanoparticles (~3 nm) with atomically dispersed Cu and an in situ formed surface oxide layer. Benefiting from the synergistic electronic modulation induced by Cu incorporation and surface oxidation, the d-band center of Ru is downshifted, leading to weakened *OH adsorption and optimized hydrogen adsorption free energy (ΔG H ). As a result, RuCuO exhibits outstanding HER performance in alkaline media, delivering a low overpotential of 27.5 mV at 10 mA cm −2 and a small Tafel slope of 24.2 mV dec −1 , surpassing commercial Pt/C. Mechanistic investigations combining X-ray absorption spectroscopy and density functional theory calculations reveal that the surface oxide layer not only suppresses *OH poisoning but also enhances H 2 O adsorption and dissociation. This work provides a viable strategy for designing high-performance alkaline HER catalysts through surface oxidation engineering of single-atom alloys. A surface-oxidized RuCu nanoalloy was prepared via pulsed laser irradiation in liquids (PLIL), enabling in situ surface oxidation and electronic structure modulation. The optimized surface electronic environment tunes OH adsorption and delivers enhanced hydrogen evolution activity. Download: Download high-res image (126KB) Download: Download full-size image