Optical and photocatalytic properties of Pt-photodeposited sol–gel TiO2 thin films

Platinized TiO2 films were prepared by photodepostion of platinum on the sol–gel TiO2 films. The prepared Pt/TiO2 films exhibited excellent optical and photocatalytic properties. Under photodeposition conditions used in this work, the amount of Pt loading was extremely small and photodeposited Pt particles were well dispersed on the TiO2 films. At the optimum Pt loading where the photoactivity becomes the maximum, about 90% of gaseous benzene was decomposed after UV illumination for 60 min. Below the optimum Pt loading, the effect of recombination retardation of electron-hole pairs prevailed over the shading effect of TiO2 surface by Pt particles. Above the optimum Pt loading, the shading effect played an important role. Above the optimum Pt loading, the photoactivity of the Pt/TiO2 films was still superior to that of the unloaded TiO2 films in the case of UV illumination, while the former was inferior to the latter in the case of fluorescent illumination.