Antimicrobial activity of Fe–TiO2 thin film photocatalysts

Fe–TiO2 sol–gel thin film photocatalysts were prepared by the spin-coating method. Precursory Fe–TiO2 films, containing 3 and 5 wt.% Fe, were thermally treated at 400 and 800 °C; the dominant crystalline phases of TiO2 were anatase and rutile, respectively. The thin films were characterized by X-ray diffraction, UV–vis spectroscopy, and scanning electron microscopy. The antimicrobial photocatalytic activity over colonies of Escherichia coli bacteria, deposited on the thin films and induced by the incidence of visible radiation was evaluated by the plate counting method. The thin film containing 5 wt.% Fe and treated at 800 °C had a microcrystalline texture and could eliminate E. coli bacteria completely after 60 min. In these materials the active phases are both anatase and rutile.