Enhancing Photocatalytic Pollutant Degradation through S-Scheme Electron Transfer and Sulfur Vacancies in BiFeO3/ZnIn2S4 Heterojunctions

Photocatalytic degradation plays a crucial role in wastewater treatment, and the key to achieving high efficiency is to develop photocatalytic systems that possess excellent light absorption, carrier separation efficiency, and surface-active sites. Among various photocatalytic systems, S-type heterojunctions have shown remarkable potential for efficient degradation. This work delves into the construction of S-type heterojunctions of ternary indium metal sulfide and bismuth ferrite nanofibers with the introduction of sulfur vacancy defects and morphology modifications to enhance the photocatalytic degradation performance. Through the impregnation method, BiFeO3/ZnIn2S4 heterojunction materials were synthesized and optimized. The 30% BiFeO3/ZnIn2S4 heterojunction exhibited superior photocatalytic performance with higher sulfur vacancy concentration than ZnIn2S4. The in-situ XPS results demonstrate that the electrons between ZnIn2S4 and BFO are transferred via the S-Scheme, and after modification, ZnIn2S4 has a more favorable surface morphology for electron transport, and its flower-like structure interacts with the nanofibers of BFO, which has a further enhancement of the reaction efficiency for degrading pollutants. This exceptional material demonstrated a remarkable 99% degradation of Evans blue within 45 min and a significant 68% degradation of ciprofloxacin within 90 min. This work provides a feasible idea for developing photocatalysts to deal with the problem of polluted water resources under practical conditions.