Synergy of Ni single atom and RuNi alloy nanocluster enables boosted hydrogen evolution at industrial current densities

Abstract

Ruthenium (Ru) has emerged as a promising alternative to platinum (Pt) for alkaline hydrogen evolution reaction (HER), yet its practical application is severely hindered by sluggish water dissociation kinetics and unfavorable hydrogen adsorption behavior. Herein, we strategically address these challenges by integrating Ni single-atom sites with RuNi alloy nanoclusters. The as-designed Ru₃Ni-N-C catalyst achieves exceptional alkaline HER performance, with an ultralow overpotential of 5 mV at 10 mA cm^-2. When applied in an anion exchange membrane water electrolyzer (AEMWE), the catalyst delivers a high price activity of 515.3 A dollar^-1 at 2 V and operates stably at an industrial-level current density of 500 mA cm^-2 for 200 h with a minimal degradation rate of 56.7 μV h^-1, significantly outperforming commercial Pt/C (51.9 A dollar^-1 at 2 V, 718.9 μV h^-1). Experimental and theoretical calculation studies reveal that Ni single-atom facilitates water dissociation by regulating the interfacial water structure while alloying Ni with Ru optimizes hydrogen adsorption free energy, thus accelerating the Heyrovsky step kinetics. The synergistic interplay between Ni single-atom and Ru₃Ni alloy nanocluster effectively balances intermediate adsorption and reaction kinetics, offering a rational design principle for advanced alkaline HER electrocatalysts toward scalable hydrogen production.