fig20
Figure 20. Photocatalytic systems: (A) Single excitation photosystem with a wide band gap; (B) Multiple excitation system with a pair of narrow band gap photocatalysts connected with a heterojunction; (C) Multiple excitation system connected with an electron mediator to form a Z scheme. This figure is reproduced with permission from Ref.[68], © 2021 Elsevier B.V. All rights reserved.






