p–n-Type\nLaCoO<sub>3</sub>/NiFe LDH Heterostructures\nfor Enhanced Photogenerated Carrier-Assisted Electrocatalytic Oxygen\nEvolution Reaction

The\noxygen evolution reaction (OER) poses a significant kinetic\nchallenge for various critical energy conversion and storage technologies\nincluding electrocatalytic water splitting and metal–air batteries.\nIn this study, a LaCoO<sub>3</sub>/NiFe layered double hydroxide (LDH)\ncatalyst was synthesized through the <i>in situ</i> growth\nof n-type NiFe LDH on the surface of the p-type LaCoO<sub>3</sub> semiconductor,\nresulting in a p–n heterostructure for a photogenerated carrier-assisted\nelectrocatalytic OER (PCA-eOER). The alignment of their band structures\nfacilitates the formation of an internal electric field at the heterojunction\ninterface, which promotes the creation of oxygen vacancies and enhances\nelectron transport. Under illumination, the expanded visible-light\nabsorption range and built-in electric field work synergistically\nto improve the generation and separation of photogenerated carriers.\nMeanwhile, the accumulation of photogenerated holes on the surface\nof NiFe LDH results in an enhancement in the concentration of high-valent\nactive metal sites, resulting in a boost in the PCA-eOER efficiency.\nThe LaCoO<sub>3</sub>/NiFe LDH has achieved an overpotential of 260\nmV at the current density of 10 mA cm<sup>–2</sup>, 50 mV lower\nthan in the absence of illumination. In addition, LaCoO<sub>3</sub>/NiFe LDH was assembled into an alkaline water electrolyzer and zinc–air\nbatteries (ZABs), showing excellent practical application capability.\nWe explored the application of LaCoO<sub>3</sub> in a PCA-eOER, which\nprovides a concept for designing PCA-eOER catalysts and advancing\nthe development of perovskite-based catalysts for clean energy conversion\ntechnology.