Mini review on electron mediator in artificial photosynthesis: Design, fabrication, and perspectives based on energy level matching

Photocatalysis based on artificial photosynthesis is an effective method for addressing the current energy crisis and environmental issues. During photocatalysis, the charge transfer between the photocatalytic reduction and oxidation reactions constitutes the rate-limiting step of the entire Z-scheme photocatalytic system. The primary factors in building a highly efficient photogenerated charge-transfer interface include the design and fabrication of appropriate solid electron mediators. These factors are crucial for improving the performance of artificial photosynthesis systems, which include overall water splitting, hydrogen evolution, CO₂ photocatalytic reduction and pollutant degradation. Herein, we review the current literature on solid electron, including (noble) metals, metal oxides/sulfides, and carbon-based materials, in artificial photosynthesis, analyze the advantages and disadvantages of various electron mediators, and summarize the properties of electron mediators that facilitate the rapid separation of photogenerated charges. Moreover, we provide further perspectives for the energy level matching of the interface between electron mediators and catalysts in artificial photosynthesis based on work function regulation.