Surface Restructuring of Zeolite‐Encapsulated Halide Perovskite to Activate Lattice Oxygen Oxidation for Water Electrolysis

Abstract Metal‐halide perovskites possess great potential for electrochemical water splitting that has not been realized due to their intolerance to water. Here, methylammonium lead halide perovskites (MAPbX₃) are used to electrocatalyze water oxidation in aqueous electrolytes by creating MAPbX₃@AlPO‐5 host–guest composites. Due to the protective feature of the zeolite matrix, halide perovskite nanocrystals (NCs) confined in aluminophosphate AlPO‐5 zeolites achieve an excellent stability in water. The resultant electrocatalyst undergoes dynamic surface restructuring during the oxygen evolution reaction (OER) with the formation of an edge‐sharing α‐PbO₂ active layer. The existence of charge‐transfer interactions at the MAPbX₃/α‐PbO₂ interface significantly modulates the surface electron density of the α‐PbO₂ and optimizes the adsorption free energy of oxygen‐containing intermediate species. Furthermore, the soft‐lattice nature of halide perovskites enables more facile triggering of lattice‐oxygen oxidation of nanostructured α‐PbO₂, exhibiting pH‐dependent OER activity and non‐concerted proton‐electron transfer for MAPbX₃@AlPO‐5 composite. As a result, the developed MAPbBr₃@AlPO‐5 composite manifests an ultralow overpotential of 233 mV at 10 mA cm⁻² in 1 m KOH. These findings offer facile access to halide perovskite applied to water electrolysis with enhanced intrinsic activity, providing a new paradigm for designing high‐efficiency OER electrocatalysts.