Efficient levofloxacin degradation and Cr(VI) reduction by S-scheme MoO3@SnIn4S8 heterostructure

Abstract

The increasing discharge of pharmaceuticals and heavy metals into aquatic environments poses serious ecological threats, creating an urgent need for effective wastewater treatment technologies. In this study, a MoO₃@SnIn₄S₈ heterojunction photocatalyst was successfully produced via a facile straightforward hydro/solvothermal technique for photocatalytic degradation of both levofloxacin (LEV) antibiotics and hexavalent chromium (Cr(VI)). The optimized MS-0.05 heterojunction exhibited exceptional photocatalytic performance, achieving 94.5 % degradation of LEV (40 mg/L) within 50 min using only 0.2 g/L catalyst, significantly outperforming pristine MoO₃ (5 %) and SnIn₄S₈ (80.4 %). For Cr(VI) reduction, the heterojunction at a dosage of 0.5 g/L accomplished complete removal of 20 mg/L Cr(VI) within 50 min, demonstrating remarkable improvements over the individual components (MoO₃: 7.4 %; SnIn₄S₈: 66.7 %). Comprehensive characterization and theoretical analysis revealed an S-scheme charge transfer pathway governing the photocatalytic process. These findings demonstrate the great potential of MoO₃@SnIn₄S₈ heterojunction as an efficient dual-functional photocatalyst for removing both pharmaceutical contaminants and heavy metals in wastewater treatment applications.