Scale Differentiation Tuning of Electronic Metal–Support Interactions to Construct a Robust Ruthenium‐Based Catalyst for Efficient Hydrogen Evolution

Low-cost, efficient hydrogen evolution reaction (HER) catalysts are crucial for the industrialization of water electrolysis. While Ru-based catalysts offer promise as Pt alternatives, conventional Ru-based catalysts are limited by their poor activity and low utilization rate. To overcome this, a differently scaled Ru single-atom/nanocluster (Ru_SA/NC) structure on 3D ordered hierarchical porous N-doped carbon (3DOM-NC) is designed, which optimizes electronic metal-support interaction through scale differentiation of the active sites. This dual-site catalyst leverages high atomic utilization efficiency and superior water dissociation capability to deliver exceptional intrinsic HER activity, achieving a turnover frequency (TOF) value at 100 mV overpotential 7.7 times greater than commercial Pt/C. Investigations reveal that N-anchored Ru single atoms modulate the electronic structure of adjacent nanoclusters, downshifting the Ru d-band center. This optimization of reaction intermediate adsorption energy, combined with synergistic site interactions, significantly lowers the HER energy barrier. Critically, the catalyst demonstrated robust stability for over 130 h at 100 mA cm^-2 during overall water splitting in an anion exchange membrane electrolyzer. This work presents a novel strategy for designing highly active and stable electrolytic catalysts for hydrogen production.