The Bi-Modified (BiO)2CO3/TiO2 Heterojunction Enhances the Photocatalytic Degradation of Antibiotics

Abstract

The increasing concentration of antibiotics in natural water poses a significant threat to society’s sustainable development due to water pollution. Photocatalytic technology is an efficient and environmentally friendly approach to environmental purification, offering great potential for addressing pollution and attracting significant attention from scholars worldwide. TiO2, as a representative semiconductor photocatalytic material, exhibits strong oxidation ability and excellent biocompatibility. However, its wide band gap and the rapid recombination of photo-generated electron–hole pairs significantly limit its photocatalytic applications. Recent studies indicate that constructing heterojunctions with synergistic plasmonic effects is an effective strategy for developing high-performance photocatalysts. In this study, Bi metal nanoparticles and (BiO)2CO3 nanosheets were simultaneously grown on TiO2 nanofibers via an in situ hydrothermal method, successfully forming a Bi@(BiO)2CO3/TiO2 composite fiber photocatalyst with synergistic plasmonic effects. The surface plasmon resonance (SPR) effect of Bi nanoparticles combined with the (BiO)2CO3/TiO2 heterojunction enhances sunlight absorption, facilitates efficient separation of photo-generated carriers, and significantly strengthens the photo-oxidation and reduction abilities. This system effectively generates abundant hydroxyl (·OH) and superoxide (·O2−) radicals under sunlight excitation. Consequently, Bi@(BiO)2CO3/TiO2 exhibited outstanding photocatalytic performance. Under simulated sunlight for 60 min, the photodegradation efficiencies of the quinolone antibiotics lomefloxacin, ciprofloxacin, and norfloxacin reached 93.2%, 97.5%, and 100%, respectively. Bi@(BiO)2CO3/TiO2 also demonstrates excellent stability and reusability. This study represents a significant step toward the application of TiO2-based photocatalyst materials in environmental purification.