Artificial Z-scheme photocatalytic system: What have been done and where to go?

Artificial Z-scheme photocatalysis has become a potential solution for resisting environmental degradation and to the worldwide energy shortage because they can effectively promote the separation of photogenerated electron-hole pairs and optimize the oxidation and reduction ability of the photocatalytic system. Currently, the application of Z-scheme photocatalysts in environmental remediation and energy conversion have ushered in a climax over the past several years. Hence, it is the ripe and right period to provide a comprehensive and state-of-the-art review on the latest achievements and the future trends of Z-scheme photocatalysis. Here, we begin with a review about the historical development of the Z-scheme photocatalytic system from redox-mediator Z-scheme photocatalytic system to current direct Z-scheme photocatalytic system. Then the latest research activities on the application of Z-scheme photocatalysts for target organic pollutants degradation, heavy metal ion redox, micro-organisms inactivation, water splitting, H-2 and O-2 evolution are systematically summarized and highlighted. Many recent advances in Z-scheme photocatalysis have been achieved by increasing the absorption region of visible light or promoting the separation and transfer of photogenerated charge carriers to achieve optimal photocatalytic performance. Especially, we discuss the charge carrier transfer process and photocatalytic reaction pathways of key aspects of Z-scheme photocatalysts. Finally, conclusions and inspiring perspectives on the challenges of this emerging research direction are presented. We desire that insights and up-to-date information in this overview will prompt the scientific community to fully explore the potential of Z-scheme photocatalytic systems in environmental remediation and energy conversion. (C) 2018 Elsevier B.V. All rights reserved.