Preparation of Titanium−Silicon Binary Oxide Thin Film Photocatalysts by an Ionized Cluster Beam Deposition Method. Their Photocatalytic Activity and Photoinduced Super-Hydrophilicity

Titanium−silicon binary oxide thin films of differing TiO 2 content were prepared by using an ionized cluster beam (ICB) deposition method using multi-ion sources under a dry preparation process. From the results of UV−vis absorption measurements, binary oxide thin films with low TiO 2 content showed much higher transmittance as compared with the pure TiO 2 thin film, indicating that the Ti−oxide species of these Ti−Si binary oxide thin films exist in a highly dispersed state within the SiO 2 matrices. Ti K-edge XAFS measurements revealed that such binary oxide thin films with low TiO 2 content (less than 20%) showed only a sharp preedge peak attributed to the highly dispersed Ti−oxide species which are different from the peaks of anatase TiO 2 thin films. Moreover, they were found to exhibit much higher and more efficient photocatalytic reactivity for the decomposition of NO into N 2 and O 2 under UV light irradiation than the pure TiO 2 thin films.