Visible light response of Ag+/TiO2–Ti2O3 prepared by photodeposition under foam fractionation

An Ag+/TiO2–Ti2O3 nanocomposite was synthesized by a novel foam fractionation method: the foam traveled to a fixed vertical column and was fractionated. Silver was deposited (0–0.02 mol%) on titania photocatalytic nanoparticles by the foam fractionation method under UV irradiation. By TEM, the Ag particles were found to be highly dispersed on TiO2 without any aggregation. XPS studies revealed the presence of both the Ti3+ and Ti4+ forms, and with an increase in Ag content, Ti3+ increased. Ag was found mainly in the Ag+ state. The obtained Ag–Ti oxides were investigated for photocatalytic activity by the degradation of methylene blue under visible light and sunlight, and the catalytic activity was better under sunlight than under visible light. The activity was found to increase with an increase in Ag loading. The Ag+/TiO2–Ti2O3 obtained by the foam fractionation method was further investigated for bactericidal activity under visible light. Using 0.05 mol% Ag/Ti, the bacterial growth of Escherichia coli was completely inhibited under visible light.