Boosting charge transfer at inorganic/organic S-scheme interface for photo-Fenton degradation of antibiotics and bacterial inactivation

Solar-driven Fenton-like reactions are promising strategies for degrading pharmaceutical wastewater to address environmental challenges and antibiotic pollution. However, its efficacy is limited by suboptimal light absorption efficiency, rapid charge recombination, and inadequate interfacial charge transfer. In this study, an inorganic/organic S-scheme photo-Fenton system of pseudobrookite/carbon nitride (FTOCN) was synthesized via a hydrothermally coupled calcination process for the effective purification of tetracycline antibiotics under visible-light irradiation. The optimized FTOCN-2 heterostructure exhibits a significantly enhanced TC degradation capacity of 90% within 60 min. The rate constant of FTOCN-2 is 1.6 and 5.2 times greater than those of FTO and CN, respectively. Furthermore, FTOCN exhibits high antibacterial efficacy, highlighting its potential application in the purification of natural water. Measurements via a range of analytical techniques, including Kelvin probe force microscopy, density functional theory calculations, in situ X-ray photoelectron spectroscopy, and femtosecond transient absorption spectroscopy, corroborate the S-scheme mechanism. This study provides a novel perspective for the development of photo-Fenton systems with S-scheme heterojunctions for water purification.