Cu-Doped Heterointerfaced Ru/RuSe₂ Nanosheets with Optimized H and H₂O Adsorption Boost Hydrogen Evolution Catalysis

Ruthenium chalcogenide is a highly promising catalytic system as a Pt alternative for hydrogen evolution reaction (HER). However, well-studied ruthenium selenide (RuSe₂) still exhibits sluggish HER kinetics in alkaline media due to the inappropriate adsorption strength of H and H₂O. Herein, xx report a new design of Cu-doped Ru/RuSe₂ heterogeneous nanosheets (NSs) with optimized H and H₂O adsorption strength for highly efficient HER catalysis in alkaline media. Theoretical calculations reveal that the superior HER performance is attributed to a synergistic effect of the unique heterointerfaced structure and Cu doping, which not only optimizes the electronic structure with a suitable d-band center to suppress proton overbinding but also alleviates the energy barrier with enhanced H₂O adsorption. As a result, Cu-doped heterogeneous Ru/RuSe₂ NSs exhibit a small overpotential of 23 mV at 10 mA cm⁻², a low Tafel slope of 58.5 mV dec⁻¹ and a high turnover frequency (TOF) value of 0.88 s⁻¹ at 100 mV for HER in alkaline media, which is among the best catalysts in noble metal-based electrocatalysts toward HER. The present Cu-doped Ru/RuSe₂ NSs interface catalyst is very stable for HER by showing no activity decay after 5000-cycle potential sweeps. This work heralds that heterogeneous interface modulation opens up a new strategy for the designing of more efficient electrocatalysts.