Nitrogen-vacancy-regulated plasmonic schottky interfaces on ag/C3N5 for ultrafast oxygen activation and solar-driven antibiotic degradation

Carbon nitride can be used in solar photocatalysis for treatment of antibiotic contaminants; however it often suffers exciton trapping and sluggish interfacial electron transfer, limiting O 2 activation. Herein, nitrogen-vacancy-regulated plasmonic Schottky interfaces are constructed by introducing N vacancies into C 3 N 5 and anchoring Ag nanoparticles (CNV-Ag). Under AM 1.5G irradiation, CNV-Ag achieves ~100% sulfamethoxazole removal within 60 min, giving an apparent rate constant ~75× higher than pristine C 3 N 5 . The catalyst performs robustly in complex water matrices, degrades multiple antibiotics, and remains stable in flow operation with 94.4% outlet removal over 6 h. Quenching and electron paramagnetic resonance spectroscopy identify •O 2 − , h + , and 1 O 2 as the dominant oxidants. The theoretical calculations reveal that N vacancies upshift the Fermi level, enhance interfacial charge exchange, lower the work function, and promote band bending to favor O 2 reduction. This paradigm offers a general blueprint for coupling defect chemistry with plasmonic charge management to enable scalable, solar-driven oxidative technologies for broad-spectrum water purification.