Green Synthesis of Ag/TiO₂ Nanoparticles: Properties and Antibacterial Potential for Environmental Applications

The spread of bacteria resistant to multiple drugs has required the development of new strategies for treating infections. Light-activated materials are emerging as a promising alternative, as they can inactivate bacteria by generating reactive oxygen species (ROS), without inducing resistance. Based on this search for new materials, silver (Ag) catalysts (2% and 10%) supported on titanium dioxide (TiO₂) were synthesized via modified sol-gel synthesis, utilizing tapioca as a sustainable gelling agent. The Ag/TiO₂ catalysts (2AgT/V and 10AgT/V) characterized by spectra in the infrared region showed characteristic titanium bands, asymmetric Ti-Ag-O vibration and Ag-TiO₂ bonding, confirming the deposition of Ag on the support. X-ray diffraction identified characteristic peaks of metallic Ag and the anatase phase for the AgT/V catalysts, representing organized crystalline phases. Antibacterial assays demonstrated the high efficiency of the 10AgT/V catalyst, achieving a 98% reduction in Escherichia coli growth in 15 min in the absence of light, suggesting an intrinsic antimicrobial effect of Ag. Photoactivation of the 10AgT/V catalyst under black light reduced E. coli and Staphylococcus aureus by 85% and 84%, respectively, in 15 min. The production of ROS, confirmed in the detection test, along with the intrinsic action of Ag, explains the high performance of these catalysts. These results demonstrate the potential of AgT/V catalysts for the development of antimicrobial coatings, contributing to the prevention and control of infections in various environments.