Photocatalytic and Antibacterial Properties of Ag-Doped TiO₂ Nanoparticles Synthesized via Sol-Gel Method

Abstract

Silver-doped titanium dioxide (Ag–TiO₂) nanomaterials have emerged as promising multifunctional agents for environmental remediation and biomedical applications. In this study, Ag–TiO₂ nanoparticles were synthesized using a sol-gel route with controlled silver concentrations (0–5 wt%). X-ray diffraction revealed anatase-dominated phases with slight peak broadening due to lattice distortion from Ag incorporation. Transmission electron microscopy indicated nanoparticle sizes between 15–25 nm. UV–Vis diffuse reflectance spectroscopy showed bandgap narrowing from 3.2 eV to 2.9 eV, enhancing visible light absorption. Photocatalytic activity, tested via methylene blue degradation, demonstrated a 93% removal rate within 120 minutes under simulated solar irradiation for 3 wt% Ag–TiO₂, outperforming pristine TiO₂ by nearly 35%. Antibacterial assays against E. coli and S. aureus confirmed strong inhibition zones, attributed to synergistic photocatalytic ROS generation and Ag ion release. Reusability tests across four cycles showed sustained efficiency, confirming material stability. These findings highlight Ag–TiO₂ as a cost-effective nanomaterial for integrated wastewater treatment and antibacterial applications.