Single‐Atom Ruthenium Anchored on Ni ₄ Mo/NiMoO ₄ : Leveraging Metal‐Support Interaction for Superior Bifunctional Water Electrolysis

Achieving efficient and stable bifunctional water electrolysis catalysis at industrial-scale current densities is a key challenge for large-scale green hydrogen applications. Herein, we employ an innovative hydrothermal-annealing coupled reduction strategy to fabricate a single-atom ruthenium-anchored Ni₄Mo/NiMoO₄ hierarchical needle-like morphology catalyst (Ru-Ni₄Mo/NiMoO₄). Owing to robust metal-support interactions (MSI), this catalyst demonstrates exceptional bifunctional activity and exceptionally high stability in alkaline electrolyte conditions. At an industrial-scale current density of 500 mA cm⁻², the overpotentials for HER and OER are only 140 and 420 mV, respectively, exceeding the performance of commercial Pt/C and RuO₂ catalysts. Of particular note, the catalyst exhibits exceptional operational stability over an extended duration exceeding 700 h at 500 mA cm⁻². Mechanistic studies indicate that single-atom Ru tailors the electronic structure through MSI, thereby modulating the adsorption energy of key intermediates, while the needle-like morphology enhances mass transfer and bubble desorption. This work presents a novel strategy for designing water-splitting catalysts with high current density and long lifetime.