Enhanced Hydrogen Evolution Reaction in Alkaline Media via Ruthenium–Chromium Atomic Pairs Modified Ruthenium Nanoparticles

Precisely optimizing the electronic metal support interaction (EMSI) of the electrocatalysts and tuning the electronic structures of active sites are crucial for accelerating water adsorption and dissociation kinetics in alkaline hydrogen evolution reaction (HER). Herein, an effective strategy is applied to modify the electronic structure of Ru nanoparticles (Ru_NPs) by incorporating Ru single atoms (Ru_SAs) and Ru and Cr atomic pairs (RuCr_APs) onto a nitrogen-doped carbon (N-C) support through optimized EMSI. The resulting catalyst, Ru_NPs-RuCr_APs-N-C, shows exceptional performance for alkaline HER, achieving a six times higher turnover frequency (TOF) of 13.15 s⁻¹ at an overpotential of 100 mV, compared to that of commercial Pt/C (2.07 s⁻¹). Additionally, the catalyst operates at a lower overpotential at a current density of 10 mA·cm⁻² (η₁₀ = 31 mV), outperforming commercial Pt/C (η₁₀ = 34 mV). Experimental results confirm that the RuCr_APs modified Ru_NPs are the main active sites for the alkaline HER, facilitating the rate-determining steps of water adsorption and dissociation. Moreover, the Ru-Cr interaction also plays a vital role in modulating hydrogen desorption. This study presents a synergistic approach by rationally combining single atoms, atomic pairs, and nanoparticles with optimized EMSI effects to advance the development of efficient electrocatalysts for alkaline HER.