Fe Single Atom Enabled Ni Dual Sites Unlock the Oxide Pathway for Efficient Oxygen Evolution

ABSTRACT Activating the oxide path mechanism (OPM) at Ni sites toward oxygen evolution reaction (OER) is particularly challenging due to the strict geometric and electronic requirements for * O─ * O radical coupling. Here, we designed paired Ni atom centers (Ni 2 ) and Ni 2 ‐Fe dual centers to elucidate and regulate the OER pathway. Both catalysts possess a Ni 2 (N/O) 6 moiety, while the incorporation of a neighboring Fe atom in Fe─O 4 coordination induces steric and electronic modulation. This modification enables the adjacent Ni site to couple with an * O species on the other Ni, forming Ni─O─O─Ni intermediates that unlock the OPM‐dominant behavior. Such a mechanism weakens Ni─O bonds, promotes coordination switching, and significantly lowers the reaction barriers. Benefiting from this effect, Ni 2 ‐Fe requires only 232 mV to reach 10 mA cm −2 at an ultra‐low Ni loading of 3.75 µg cm −2 , achieving a record‐high mass activity of 25780 A g −1 at 300 mV. Electrolyzer tests at 60°C further demonstrate a low operation voltage of 1.91 V at 1000 mA cm −2 and stable durability for 200 h at 200 mA cm −2 . This work establishes a single‐atom Fe modulation strategy to trigger the OPM pathway at Ni sites, providing new mechanistic insights and design principles for advanced OER electrocatalysts.