Photo-Fenton degradation of tetracycline over Z-scheme Fe-g-C3N4/Bi2WO6 heterojunctions: Mechanism insight, degradation pathways and DFT calculation

Herein, Fe-g-C3N4/Bi2WO6 Z-scheme heterojunction is elaborately designed to build a photo-Fenton system for the degradation of tetracycline (TC). In this study, the H2O2 decomposition performance of the Z-scheme heterojunction has been improved due to the doping of iron, improve photogenerated electrons transportability and facilitate spread of radicals, according to the efficacy analyses, and trapping experiment, ESR analysis as well as degradation pathways of TC. Moreover, DFT theoretical results suggest that the Z-scheme transfer route coupled with the generated photo–Fenton process builds a Z-scheme-charge-transfer platform for remarkable degradation of emerging pollutants, and the formation of Fe-N4 sites induces a spin polarization of the material and also introduces a defect state in the original forbidden band, which leads to extremely activity for the removal of TC in the photo-Fenton system. The study shows that 1O2 and •O2− are the main active species participating in the degradation process.