Efficient photocatalytic tetracycline elimination over Z-scheme g-C3N4/Bi5O7I heterojunction under sunshine light: Performance, mechanism, DFT calculation and pathway

A series of Z-scheme heterojunction g-C3N4/Bi5O7I composites were fabricated via a facile electrostatic selfassembly procedure. The optimum 15%-g-C3N4/Bi5O7I displayed good degradation efficiency toward tetracycline (TC) under visible light irradiation. The improvement of photocatalytic efficiency was mainly attributed to the generation of photo-induced h+ and O2 center dot- radical. The migration route of photo-induced h+ and e- between g-C3N4 and Bi5O7I was investigated by XPS analysis, EPR test, photocatalytic mechanism and DFT calculations. The degradation pathways and the toxicological simulation of TC were evaluated. It was revealed that the intermediates produced during degradation process exhibited lower toxicity than the pristine TC. In addition, 15%-g-C3N4/Bi5O7I exhibited good stability and reusability. Considering its potentials in practical application, 15%-g-C3N4/Bi5O7I displayed high photocatalytic efficiency under natural sunlight irradiation. In all, this work offered a deep insight into the photocatalytic mechanism of tetracycline degradation over bismuth-rich bismuth oxyhalide/g-C3N4 heterojunction photocatalysts.(c) 2023 Elsevier B.V. All rights reserved.

Automated summary

A series of Z-scheme heterojunction g-C3N4/Bi5O7I composites were successfully synthesized using an electrostatic self-assembly method. The optimized 15%-g-C3N4/Bi5O7I exhibited efficient degradation of tetracycline under visible light irradiation, attributed to the generation of photo-induced h+ and O2•- radicals. The migration of photo-induced h+ and e- between g-C3N4 and Bi5O7I was investigated, and the degradation pathways and toxicological simulation of tetracycline were evaluated. The composite also demonstrated good stability and reusability, making it a promising photocatalyst for practical applications.