Strongly Coupled 0D Tea Biomass Quantum Dots/2D PbBiO2Br Nanosheets for Robust Photocatalytic Degradation of Antibiotics: Boosting Molecular Oxygen Activation and Mechanism Insight

The activation of molecular oxygen driven by solar energy presents a cost-effective and environmentally friendly approach in the area of environmental purification. Carbon quantum dots and semiconductor nanocomposite photocatalysts serve as an effective strategy for enhancing the separation and transport of photogenerated carriers, thereby boosting the activation of molecular oxygen. In this study, we prepared 0D tea biomass quantum dots (T-BCDs) coupled with 2D PbBiO2Br nanosheets, which demonstrate enhanced molecular oxygen activation under visible light irradiation and were synthesized using a solvothermal method. Transmission electron microscopy (TEM) analysis reveals that T-BCDs, with diameters of approximately 5 nm, are uniformly distributed on the surface of PbBiO2Br. Notably, experimental results indicate a strong covalent interaction between PbBiO2Br and T-BCDs, which enhances the absorbance of visible light, facilitates the transfer and separation of interfacial photogenerated carriers, and promotes the conversion of molecular oxygen into superoxide radicals. The degradation rate constant of ciprofloxacin achieved with 5 mL T-BCDs/PbBiO2Br is 3.3 times greater than that obtained with pure PbBiO2Br. This research offers a promising strategy for the development of efficient 0D/2D photocatalysts aimed at sustainable environmental remediation.