Photocatalytic and bactericidal activity of mesoporous TiO2–Ag nanocomposite particles

Mesoporous TiO 2 –Ag composite particles with raspberry-like morphology were prepared by a two-step chemical route and their photocatalytic and bactericidal properties were examined. Ag nanoclusters of about 50 nm in diameter were decorated on surface of submicrometer, anatase TiO 2 particles with Ag concentration of 3.8±0.4 at%; in which, the TiO 2 particles were mesoporous with an average pore diameter of 9.3 nm and a BET surface area of 147.5 m 2 g −1 . The composite particles enhanced the photocatalytic degradation of methylene blue (MB) dye in water under ultraviolet irradiation when compare to that of the bare TiO 2 . Removal of the MB dye with an initial concentration of 1×10 −5 M was completed within an hour and the degradation rate of the MB dye was found independent of temperature employed. In addition, the composite particles imparted bactericidal activity against gram-negative Escherichia coli in aqueous solutions under dark condition, enabling hence bifunctional activities under both light and dark situations.