Synthesis of TiO2–Ag nanocomposite with sol–gel method and investigation of its antibacterial activity against E. coli

TiO2–Ag nanocomposite was prepared by the sol–gel method and an azeotropic distillation with benzene was used for dehydration of the gel. Because of gel dehydration by distillation method a nanopowder with a surface area of 230 m2/g was produced which decreased to 80 m2/g after calcination. TEM micrographs and XRD patterns showed that spherical nanosized Ag particles (≈ 10 nm) were deposited among TiO2 particles. The antibacterial activity of calcined powder at 300 and 500 °C was studied in the presence and in the absence of UV irradiation against Escherichia coli as a model for Gram-negative bacteria. The antibacterial tests confirmed the powder calcined at 300 °C possessed more antibacterial activity than the pure TiO2, amorphous powder and the powder calcined at 500 °C under UV irradiation. In the absence of UV, the reduction in viable cells was observed only with calcinated powder at 300 °C.