Atom-Cluster Synergy in Scalable Fe-Ru Dual-Site Architectures Accelerates Alkaline Hydrogen Evolution

Sluggish initial water dissociation (the Volmer step) severely limits alkaline water electrolysis. We report a highly scalable mechanochemical strategy to construct a dual-site electrocatalyst, Ru_NC@Fe₁NC, that spatially decouples water activation and hydrogen recombination. Harnessing the high-energy impact of iron media and graphite, a solvent-free mechanochemical process generates a defective carbon matrix anchoring isolated, oxophilic Fe single atoms (Fe₁), followed by the targeted deposition of ruthenium nanoclusters (Ru_NC). This atomic-level division of catalytic labor fundamentally accelerates the alkaline hydrogen evolution reaction. Ru_NC@Fe₁NC requires an overpotential of only 13.8 mV at 10 mA cm^-2 with an ultralow Ru loading (∼2 wt%). In a practical anion exchange membrane water electrolyzer (AEMWE), this catalyst drives a current density of 1.0 A cm^-2 at merely 1.66 V and sustains over 1100 h of continuous operation with negligible decay. Mechanistic studies-combining isotopic substitution, in situ Raman spectroscopy, time-resolved hydrogen accumulation-stripping analysis, and density functional theory-reveal that the Fe₁ sites readily adsorb water and selectively lower the O-H cleavage barrier, rapidly feeding hydrogen intermediates to the adjacent Ru_NC for efficient hydrogen desorption. This work establishes a robust blueprint for designing synergistic dual-site architectures to circumvent kinetic bottlenecks in green hydrogen production.