Two‐Dimentional Nanostructured Metal Oxide/Sulfide–Based Photoanode for Photoelectrochemical Water Splitting

The utilization of solar energy plays a vital role in relieving energy crisis and associated environmental problems. Photoelectrochemical (PEC) water splitting, which can directly transform solar energy into clean hydrogen energy, is one of the most promising strategies to utilize solar energy. 2D nanostructured metal oxides/sulfides have been widely applied as photoanodes in PEC cells due to their unique configuration and features, which can efficiently improve light absorption, enlarge electrode/electrolyte contacting interfaces, and promote carrier transfer and injection. This article begins with the introduction of performance parameters, carrier dynamics measurement, and mechanism exploration techniques for photoanodes, which is followed by an overview of research progress in using 2D nanostructure metal oxides/sulfides to fabricate efficient photoanodes for PEC water splitting. Subsequently, the recent representative strategies to optimize the PEC performance of 2D metal oxides/sulfides photoanodes, including structure engineering, defect engineering, element doping, heterojunction construction, and surface modification, are summarized. Finally, the exciting advances and future research directions for designing highly efficient 2D photoanodes are provided.