LSPR-enhanced Bi4O5Br2/W18O49 S-scheme heterojunction boosts ciprofloxacin degradation via photocatalytic O2 activation

The limited narrow spectral absorption and rapid recombination of photogenerated carriers in photocatalytic materials result in inefficient molecular oxygen activation and insufficient generation of reactive oxygen species (ROS), severely restricting the degradation efficiency of organic pollutants. Herein, a composite catalyst with broad visible-light responsiveness was fabricated via a facile solvothermal and room-temperature stirring strategy, where sheet-like Bi 4 O 5 Br 2 was encapsulated with W 18 O 49 nanowires. The as-prepared catalyst exhibited high concentrations of h + and O 2 − active species, achieving a 92 % degradation rate of ciprofloxacin (20 mg/L) within 60 min, alongside exceptional environmental tolerance and stability. Experimental and computational investigations confirmed the S-scheme charge transfer mechanism, which enhances carrier separation while preserving electrons and holes with strong redox capabilities. The localized surface plasmon resonance (LSPR) effect of W 18 O 49 synergistically promoted hot electrons and photogenerated electrons to activate O 2 , generating abundant O 2 − . This work proposes a novel design paradigm for efficient and stable visible-light photocatalysts, advancing solutions to emerging antibiotic pollutants in aquatic systems.