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

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 (MAPbX ) are used to electrocatalyze water oxidation in aqueous electrolytes by creating MAPbX @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-PbO active layer. The existence of charge-transfer interactions at the MAPbX /α-PbO interface significantly modulates the surface electron density of the α-PbO 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-PbO , exhibiting pH-dependent OER activity and non-concerted proton-electron transfer for MAPbX @AlPO-5 composite. As a result, the developed MAPbBr @AlPO-5 composite manifests an ultralow overpotential of 233 mV at 10 mA cm 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.