Preparation of Pt/TiO2 nanocomposite thin films by pulsed laser depositionand their photoelectrochemical behaviors

Pt/TiO2 nanocomposite films were prepared from the sintered mixture targets of Pt and TiO2 by pulsed laser deposition. Pt/Ti atomic ratios in the depo sited films are more strongly dependent on the initial content of Pt in the target than on the laser fluence. It is inferred from transmission electro n microscope, X-ray photoelectron spectroscopy and X-ray diffraction analys es that as-deposited Pt/TiO2 nanocomposite films are composed of metallic P t nanoparticles with a diameter of about 30 nm and an amorphous TiO2 matrix , which are crystallized into the dominant crystal structure of the anatase phase after the heating at 600 degreesC. The optical bandgap of Pt/TiO2 na nocomposite films was less than that of the pure TiO2 film and photolumines cence emission was observed between 680 and 800 nm at 24 K. Some energy lev els can be formed by the interface between Pt nanoparticles and TiO2, which also affect the photoelectrochemical properties of Pt/TiO2 nanocomposite e lectrodes. The anodic photocurrents at 1.0 V of Pt/TiO2 nanocomposite elect rodes were observed in the visible light range. (C) 2001 Elsevier Science B .V. All rights reserved.