Visible-Light Photocatalytic Degradation of Rhodamine B and Antibacterial Activity of Cu/Ti ³⁺ Co-Doped TiO ₂ Nanoparticles

Ti 3+ and Cu codoped TiO 2 nanophotocatalysts, denoted as Cu-BTTNs, were synthesized via a modified solvothermal method. The phase composition, surface morphology, and microstructure characteristics of the material were systematically characterized by X-ray diffraction (XRD), transmission electron microscopy (TEM), and X-ray photoelectron spectroscopy (XPS) and Fourier transform infrared spectroscopy (FT-IR). Their photocatalytic performance was evaluated under simulated visible light irradiation (xenon lamp). Using Escherichia coli ( E. coli ) and Staphylococcus aureus ( S. aureus ) as model bacteria, Cu-BTTNs (200 μg/mL) inactivated 99.74% of S. aureus and 97.26% of E. coli within 12 min (initial concentration: 1 × 10 6 CFU/mL). Simultaneously, they degraded 96.83% of Rhodamine B (RhB, 10 mg/L) within 15 min at a catalyst dosage of 1.5 mg/mL. Radical trapping experiments identified photogenerated holes (h + ), superoxide anions (·O 2 – ), and hydroxyl radicals (·OH) as the predominant reactive species responsible for bacterial inactivation and pollutant degradation. These results demonstrate that Cu/Ti 3+ codoped TiO 2 holds significant potential as a high-performance antibacterial material and an effective catalyst for dye wastewater treatment, providing a theoretical foundation for practical environmental applications.