Z-scheme p-n CoO@FeVO heterojunction-assisted peroxymonosulfate activation under visible light for boosted degradation of antibiotics: Enhanced intrinsic electric field and broadened visible-light absorption.

Overcoming rapid charge recombination remains a critical challenge in photocatalytic system development. This study reports the successful synthesis of a Z-scheme p-n heterojunction photocatalyst CoO@FeVO (CF) via hydrothermal treatment followed by high-temperature calcination to optimize the optoelectronic properties of FeVO. The engineered heterojunction interface established an intrinsic electric field that spatially segregated photogenerated charge carriers, enhancing visible-light absorption (band gap narrowing to 1.78 eV) while suppressing charge recombination. When coupled with peroxymonosulfate (PMS) activation, the CF/PMS system demonstrated exceptional antibiotic removal efficiencies within 120 min: ciprofloxacin (93.6 %), ofloxacin (88.8 %), norfloxacin (90.4 %), and tetracycline (97.1 %). Remarkably, the catalyst maintained stable ciprofloxacin degradation performance across a wide pH range (3-11) in aqueous solutions. Mechanistic investigations revealed dual degradation pathways involving both radical species (SO, ·OH and h) and non-radical species (O and e). Ecotoxicity evaluation through E. coli bioassays and computational modeling demonstrated that degradation intermediates exhibited reduced ecological hazards, with significantly lower bioaccumulation factors in aquatic organisms. This work advances the design of Z-scheme heterojunction photocatalysts for PMS-activated antibiotic removal and provides a promising strategy for sustainable water purification.