Non‐Lattice Oxygen Triggered Deprotonation via Discontinuous Amorphous Interlayer on Supported IrO _x for Acidic Oxygen Evolution

ABSTRACT Iridium‐based catalysts for the acidic oxygen evolution reaction (OER) predominantly follow the adsorbate evolution mechanism (AEM), with their intrinsic activity limited by sluggish proton‐transfer kinetics. Based on this, a strategy is proposed involving the construction of a discontinuous WO _x interlayer incorporating isolated W single atoms and amorphous WO _x clusters on supported Ir‐based catalysts. The optimized Ir/W‐TiN catalyst achieves current densities of 100 mA cm ⁻² at remarkably low overpotentials of 293 mV. Leveraging the non‐lattice oxygen from the amorphous WO _x , this design promotes a shift in the reaction pathway from the conventional AEM to an interface non‐lattice oxygen‐assisted deprotonation mechanism (IOADM), simultaneously enhancing both activity and stability. The incorporation of W species facilitates the formation of oxygen vacancies and a hydrogen‐bond network, which lowers the reaction energy barrier and accelerates deprotonation kinetics. In a proton exchange membrane water electrolyzer, the membrane electrode assembly with the Ir/W‐TiN anode exhibits a high current density exceeding 2.2 A cm ⁻² at 1.8 V. Furthermore, with a low Ir loading of 0.2 mgIr cm ⁻² , it demonstrates excellent durability, maintaining stable operation for 2000 h at 1.0 A cm ⁻² . This work provides new mechanistic insights for designing highly efficient, stable, and low‐Ir‐loaded anode catalysts via interface engineering.