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

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@RuSACoSA-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@RuSACoSA-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@RuSACoSA-NMC can make water electrolysis system possess low power consumption of 5.34 kWh per Nm(H2)(3) 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.

Automated summary

In this study, ampere-level current density hydrogen production was achieved through the synchronous modification of Volmer/Tafel kinetics using double-tuned RuCo nanoalloy and dual metal single atoms on hierarchical N-doped mesoporous carbon (RuCo@RuSACoSA-NMC). The optimized electronic structure of Ru sites and double-tuned Ru sites resulted in faster Volmer kinetics and optimized Tafel kinetics respectively, leading to ultralow HER overpotential, high mass activity, and high turnover frequency. Furthermore, RuCo@RuSACoSA-NMC exhibited low power consumption and estimated costs, making it a cost-effective catalyst for ampere-level current density hydrogen production.