Interface engineering of Z-scheme heterojunction for photocatalytic water splitting

Photocatalytic water splitting technology can directly convert solar energy into H₂ via a zero-carbon route, offering a sustainable solution for solar utilization and H₂ supply. Among various developed photocatalysts, Z-scheme heterojunction mimicking natural photosynthesis by combining two dissimilar semiconductors for redox reactions in series has unequivocally demonstrated its superiority in enhanced charge transfer, robust redox driving force, and wide optical absorption range. A comprehensive understanding on the fundamental principles of interface engineering between semiconductor components is the key to construct an efficient Z-scheme heterojunction. By focusing on different types of semiconductors, this article thoroughly expounds the coupling principles of components in binary mediator-free and ternary solid-mediator Z-scheme heterojunctions for photocatalytic water splitting, from the viewpoint of band structure alignment and interfacial electric field design. In addition to the well summarized research progresses in recent years, perspectives on the challenges and opportunities for developing advanced Z-scheme heterojunctions are provided.