Photoetching-Generated Redox Pairs in Confined Layered Structure Boost Single-Electron-Transfer-Mediated Photocatalysis

The single-electron-transfer (SET)-mediated photocatalytic process, as a sustainable and environmentally friendly strategy for synthesizing high-value-added chemicals, faces significant limitations due to rapid quenching of photoexcited electrons and low electron utilization efficiency of photocatalysts. Herein, a redox pair featuring the colocalization of high- and low-valent elements in a group was proposed to realize efficient photoelectron utilization, enabling the storage and release of photogenerated electrons. By taking bismuth oxyiodate (BiOIO₃) as a typical model framework, a photoetching strategy was developed to selectively construct iodine redox pairs (I^δ+/IO₃^-) within the polar soft [IO₃]^- layers, while maintaining the structural integrity of the [Bi₂O₂]²⁺ layers. Through comprehensive theoretical calculations and spectral analyses, it was demonstrated that the as-designed iodine redox pairs (I^δ+/IO₃^-) significantly modified the electronic structure of BiOIO₃, with prolonged charge carrier lifetimes and an increase in hot-electron density. This work offers a new strategy to improve the efficiency of electronic utilization and realize electron-mediated high-value-added chemical synthesis.