Visible-light-response 2D/2D Bi2Fe4O9/ZnIn2S4 van der Waals S-scheme heterojunction with efficient photocatalysis-self-Fenton degradation of antibiotics

Constructing a high-efficient self-sufficient photo-Fenton system for pollutant degradation without the need for additional hydrogen peroxide (H2O2) remains a significant challenge. Herein, a photocatalysis-self-Fenton system based on 2D/2D Bi2Fe4O9/ZnIn2S4 (BFO/ZIS) van der Waals S-scheme heterojunction was successfully constructed for efficient degradation of antibiotic contaminants. The optimal BFO/ZIS-3 % sample achieves an impressive tetracycline (TC) degradation rate (88.8 %, 50 mg/L) after 120 min visible light irradiation, and the apparent rate constant (kapp) for BFO/ZIS photocatalysis-self-Fenton system is 14.107 times higher than the Fenton system and 2.866 times higher than the photo-Fenton system, respectively. A series of characterization tests revealed the construction of a 2D/2D BFO/ZIS van der Waals S-scheme heterojunction, not only could create a larger interface area for providing the active sites, but also form the internal electric field for enhancing photo-generated carrier separation and migration efficiency, retaining a substantial number of photo-generated charges with high redox potentials and promoting the progression of photocatalysis-self-Fenton reactions and the conversion of Fe3+/Fe2+. This strategy presents a new avenue for developing high-efficient photocatalysis-self-Fenton system.