Bi3.64Mo0.36O6.55/Bi4O5I2 S-scheme heterojunction boosting antibiotic photodegradation: Insights from interface to performance

Bi3.64Mo0.36O6.55/Bi4O5I2 (BIM) S-scheme heterojunction with strong interfacial interaction was synthesized by calcination followed by hydrothermal treatment. The Fermi level (Ef) difference between BMO (Bi3.64Mo0.36O6.55) and Bi4O5I2 enables the coupling of the two materials to trigger electron transfer, generating an internal electric field (IEF), which facilitates the directional transfer of charge and efficiently separates the photo-induced carriers. The experimental and analytical results showed that the S-scheme heterojunction not only endowed the composites with excellent photothermal properties, but also acted as an electron transport hub to promote the photogenerated electron transfer, which in turn improved the oxidation ability of the heterojunction photocatalysts. In a visible light excited heterojunction system, BIM-34 can degrade tetracycline (TC) up to 91.6%. The analysis of the S-scheme heterojunction was further validated by Kelvin probe force microscope (KPFM), In situ x-ray photoelectron spectroscopy (XPS) and density functional theory theoretical calculations (DFT). This work provides a viable strategy for designing S-scheme heterojunction with strong interface interactions photocatalysts for antibiotics removing.