Enhanced photocatalytic tetracycline degradation by MOF-derived ZnIn2S4: performance, mechanism and environmental implications

Antibiotic residues, particularly tetracycline (TC), in aquatic environments pose a critical global challenge, demanding efficient and sustainable remediation solutions. Herein, a novel metal-organic framework (MOF)-derived ZnIn 2 S 4 photocatalyst (ZnIn 2 S 4 (MOF)) was successfully synthesized via a facile hydrothermal method, exhibiting significantly enhanced visible-light photocatalytic TC degradation performance. Compared to ZnIn 2 S 4 , the as-prepared ZnIn 2 S 4 (MOF) features a unique hierarchical morphology and optimized electronic structure. Comprehensive characterizations including XRD, XPS, SEM, BET, DRS, PL, TRPL, and transient photocurrent measurements were employed to elucidate its structural, optical, and photoelectrochemical properties. The ZnIn 2 S 4 (MOF) achieved an exceptional TC removal efficiency of 83% within 50 min under visible light. The enhanced activity is attributed to abundant active sites, improved light absorption with a narrowed bandgap of 2.14 eV, and suppressed charge recombination, as evidenced by prolonged average fluorescence lifetime and enhanced photocurrent density. Systematic investigations revealed significant influences of catalyst dosage, initial TC concentration, reaction temperature, and coexisting inorganic anions on degradation kinetics. Moreover, the catalyst demonstrated remarkable versatility toward multiple antibiotics. This work provides a rational design strategy for high-performance sulfide photocatalysts and insights into structure-activity relationships for emerging pollutant degradation.