A Review of Direct Z-Scheme Photocatalysts

Recently, great attention has been paid to fabricating direct Z-scheme photocatalysts for solar-energy conversion due to their effectiveness for spatially separating photogenerated electron-hole pairs and optimizing the reduction and oxidation ability of the photocatalytic system. Here, the historical development of the Z-scheme photocatalytic system is summarized, from its first generation ( liquid-phase Z-scheme photocatalytic system) to its current third generation (direct Z-scheme photocatalyst). The advantages of direct Z-scheme photocatalysts are also discussed against their predecessors, including conventional heterojunction, liquid-phase Z-scheme, and all-solid-state (ASS) Z-scheme photocatalytic systems. Furthermore, characterization methods and applications of direct Z-scheme photocatalysts are also summarized. Finally, conclusions and perspectives on the challenges of this emerging research direction are presented. Insights and up-to-date information are provided to give the scientific community the ability to fully explore the potential of direct Z-scheme photocatalysts in renewable energy production and environmental remediation.