Photocatalytic and bactericidal activity of mesoporous TiO2–Ag nanocomposite particles

Mesoporous TiO2–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 TiO2 particles with Ag concentration of 3.8±0.4 at%; in which, the TiO2 particles were mesoporous with an average pore diameter of 9.3 nm and a BET surface area of 147.5 m2 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 TiO2. 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.