Cu-doped Heterointerfaced Ru/RuSe 2 nanosheets with optimized H and H 2 O 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 (RuSe 2 ) still exhibits sluggish HER kinetics in alkaline media due to the inappropriate adsorption strength of H and H 2 O. Herein, w e 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 heterogeneous interface 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. This article is protected by copyright. All rights reserved.