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

Abstract Ruthenium chalcogenide is a highly promising catalytic system as a Pt alternative for hydrogen evolution reaction (HER). However, well‐studied ruthenium selenide (RuSe 2 ) still exhibits sluggish HER kinetics in alkaline media due to the inappropriate adsorption strength of H and H 2 O. Herein, xx report a new design of Cu‐doped Ru/RuSe 2 heterogeneous nanosheets (NSs) with optimized H and H 2 O 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 H 2 O adsorption. As a result, Cu‐doped heterogeneous Ru/RuSe 2 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/RuSe 2 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.