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

ABSTRACT 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 @Fe 1 NC, 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 (Fe 1 ), 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 @Fe 1 NC 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 Fe 1 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.