Engineering Interfacial Hydrogen-Bond Networks to Accelerate Lattice Oxygen Regeneration for Stable Oxygen Evolution Catalysis

The lattice oxygen oxidation mechanism (LOM), while capable of delivering high oxygen evolution reaction (OER) activity, is intrinsically constrained by sluggish lattice oxygen regeneration, inducing structural degradation and compromised operational durability. To address this fundamental limitation, we develop an interfacial anion regulation strategy in which chemisorbed oxyanions─most effectively sulfate (SO 4 2– )─reshape the interfacial hydrogen-bond network by modulating hydrated cation distribution and directly bridging water molecules. In situ spectroscopic and isotopic labeling experiments confirm a substantial enhancement in lattice oxygen reactivity coupled with a reinforced, highly connected interfacial hydrogen-bond environment. Integrated theoretical calculations elucidate the role of anchored SO 4 2–, which restructures the interfacial water. This restructuring facilitates rapid OH – supply and deprotonation, thereby accelerating the regenerative replenishment of lattice oxygen. Leveraging these advantages, the SO 4 2– -modified catalyst (NiFeOOH@SO 4 2– ) enables an anion-exchange membrane electrolyzer to deliver an industrial current density of 3.75 A cm –2 under 2.0 V. Moreover, it exhibits operational stability at 2.0 A cm –2 for 2000 h with an exceptionally low degradation rate of 0.053 mV h –1, a 10-fold improvement over the bare NiFeOOH anode. This work resolves a critical lattice oxygen regeneration challenge in LOM-based electrocatalysts and establishes interfacial anion engineering as a generalizable design paradigm for securing high activity coupled with long-term stability in oxygen-evolution electrodes.