Synthesis, characterization and antibacterial activity of silver doped TiO₂ photocatalyst

Silver was doped into TiO₂ semiconductor in order to improve the antibacterial activity of TiO₂ photocatalyst under ultraviolet and visible light radiation due to its ability to modify the band gap energy of TiO₂. Silver doped TiO₂ photocatalysts were successfully synthesized using the sonochemical method at various silver concentration i.e 1,3,5,7, and 9%. Structural studies from XRD data showed that either undoped and silver-doped TiO₂ crystallized in a single phase structure of anatase TiO₂ with I41/amd space group. UV-Vis Diffuse Reflectance spectra resulted in the bandgap energy of undoped and silver-doped TiO₂ were 3.4 eV, 3.0 eV, 3.3 eV, 3.1 eV, 3.25 eVand 2.8 eV respectively. Among those various dopant concentrations, 9% Ag-doped TiO₂ showed the highest decrease in reflectance and band gap energy. Antibacterial activity of all synthesized materials toward E. coli antibacterial activity achieved the highest value for 9% of silver-doped TiO₂ under ultraviolet and visible light irradiation. Zero viability occurred at 50mg/30mL of culture for 9% of Ag-doped TiO₂ under visible irradiation. Inhibition zone and viability test confirmed that Ag content plays a significant role in increasing the antibacterial activity of silver-doped TiO₂ photocatalyst.