Double‐Tuned RuCo Dual Metal Single Atoms and Nanoalloy with Synchronously Expedited Volmer/Tafel Kinetics for Effective and Ultrastable Ampere‐Level Current Density Hydrogen Production

Abstract Alkaline water electrolysis system is of general interest but is impeded by the unsatisfactory hydrogen evolution reaction (HER) performance under ampere‐level current density. Herein, the synchronous modification of complicated Volmer/Tafel kinetics is effectuated for attaining ampere‐level current density hydrogen production via engineering double‐tuned RuCo nanoalloy and dual metal single atoms on hierarchical N‐doped mesoporous carbon (RuCo@Ru_SACo_SA‐NMC). The electronic structure of Ru sites in dual metal single atoms can be synergistically tailored by adjacent Co atomic sites and nanoalloy, which makes it achieve faster Volmer kinetics with rapid water adsorption/dissociation and transfer rates toward adsorbed hydroxyl. While double‐tuned Ru sites in nanoalloy by adjacent alloyed Co sites and dual metal single atoms undertake optimized Tafel kinetics with boosted transfer rates toward adsorbed hydrogen. Accordingly, RuCo@Ru_SACo_SA‐NMC exhibits ultralow HER overpotential of 255 mV at 1 A cm⁻² with robust stability over 24 days, ultrahigh mass activity of 37.2 A mg_Ru⁻¹, and turnover frequency of 19.5 s⁻¹. More importantly, RuCo@Ru_SACo_SA‐NMC can make water electrolysis system possess low power consumption of 5.34 kWh per Nm³_H2 and estimated costs of 1.197 $ per kg_H2. The concept emphasized in this study provides guidance for rational design of cost‐effective catalysts with ampere‐level current density hydrogen production.