The chemical states and properties of doped TiO film 2 photocatalyst prepared using the Sol–Gel method with TiCl as a 4 precursor

TiO2 film was deposited on the silicon wafer using a Sol–Gel method with TiCl4as a precursor. The TiO2film with anatase structure was formed after annealed above 3508C for 1 h in air. The thickness of the film was about 167 nm for one coating. There was a very slight interface diffusion between TiO2 layer and Si substrate during annealing treatment, and no chemical reaction was detected. After annealed at 4008C for 1 h in air, the dopants of Pt and Pd existed as metallic Pt and PdO in TiO2 film, respectively. After the films were reduced using H2 in 4008C for 2 h, Pt existed as aggregated metallic Pt particles, while Pd existed as highly dispersed metallic Pd particles. The absorption intensity for UV and visual light can be intensified significantly, and the main absorption peak can be shifted to a higher wave number after the TiO2 film doped with Pd was reduced with H2. This resulted from the interaction between highly dispersed Pd and the TiO2 film. Pd atoms entered into the lattice of anatase TiO2film. The reduction of TiO2film doped with Pt cannot change the UV absorption due to the weak interaction between Pt and TiO2. q2000 Elsevier Science B.V. All rights reserved