| Abstract: TiO2 films were loaded on Ti, Al and glass from Ti(OC4H9)4 precursor by dip-coating method, represented by TiO2 / Ti, TiO2 / Al and TiO2 / G, respectively. XPS, AFM and phtotocatalytic reaction experiments were carried out to characterize the catalytic films. The films prepared on different substrates varies greatly in chemical composition because of the extravasation of Al, Na, Ca, and Si from Al and glass substrates, which also influences the agglomerating behavior of the precursor films, resulting in the difference of particle sizes and morphologies of TiO2 films. TiO2 / Ti was proved to possess most stable photocatalytic activity, while TiO2 /Al and TiO2 / G deactivate obviously with the increase of photocatalytic experiment runs. It is concluded that accumulation of surface carbon species such as reactive intermediate was not the dominant cause of deactivation in this research. The remarkable leaching and chemical alternation of extravasated elements brought out intergranular corrosion of TiO2 films on Al and glass, leading to the flake-off of outmost TiO2 particles. The new surface contained three chemical states of Ti: Ti4+, Ti3+ and Ti2+, which was different from the new prepared TiO2 films with high activity, possessing only Ti4+. |
