Preparation of Pt/TiO2 nanocomposite thin films by pulsed laser deposition and 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 deposited films are more strongly dependent on the initial content of Pt in the target than on the laser fluence. It is inferred from transmission electron microscope, X-ray photoelectron spectroscopy and X-ray diffraction analyses that as-deposited Pt/TiO2 nanocomposite films are composed of metallic Pt 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 nanocomposite films was less than that of the pure TiO2 film and photoluminescence emission was observed between 680 and 800 nm at 24 K. Some energy levels can be formed by the interface between Pt nanoparticles and TiO2, which also affect the photoelectrochemical properties of Pt/TiO2 nanocomposite electrodes. The anodic photocurrents at 1.0 V of Pt/TiO2 nanocomposite electrodes were observed in the visible light range. (C) 2001 Elsevier Science B.V. All rights reserved.