Solid mediator Z-scheme heterojunction photocatalysis for pollutant oxidation in water: Principles and synthesis perspectives

Background: The solid mediator Z-scheme heterojunctions are promising photocatalysts that have narrow band gaps to allow excitation of incorporated electrons under visible lights but with sufficient separation of the yielded electron hole-pairs and without suffering the reduction of their oxidization and reduction powers. Successful synthesis of mediator Z-scheme heterojunction acquires production of constituent semiconductors with desired Fermi levels and close contacts of the semiconductors with sandwiched metal mediator. Methods: This mini-review discussed briefly the principles of photocatalyst and heterojunction photocatalysts, and then the current research and development studies on the way to design and synthesis of Z-scheme heterojunction were summarized. Significant findings: Based on literature results, the perspectives to design and synthesis of a solid mediator Zscheme for degrading specific pollutant were discussed and outlined. An illustrative example of design and synthesis of a novel Z-scheme photocatalyst, CuFe2O4/Cu/UiO66-NH2, with demonstration of its photodegradation performance of dye rhodamine 6 G, was presented at the end of the review. (c) 2021 Taiwan Institute of Chemical Engineers. Published by Elsevier B.V. All rights reserved.

Automated summary

By designing and synthesizing solid mediator Z-scheme heterojunctions, efficient degradation of specific pollutants by photocatalysts can be achieved. The key to successful synthesis of Z-scheme heterojunction lies in ensuring that constituent semiconductors have desired Fermi levels and close contacts with sandwiched metal mediators.