Designed self-doped titanium oxide thin tilms for efficient visible-light photocatalysis

Anatase phase of titanium oxide is the most promising photocatalyst material for organic pollutant degradation. However, due to its large band gap energy (3.2 eV) it is not viable to use using sunlight as an energy source for the photocatalysis activation and so ultraviolet (UV) radiation below the wavelength of 380 nm is thus required. This paper focuses on the experimental demonstration of the reduction of this large band gap energy by inducing defects in the anatase structure under the form of oxygen sub-stoichiometry. TiO2 thin films were prepared in an MOCVD (Metal Organic Chemical Vapour Deposition) reactor. The samples stoichiometry was measured by the RBS (Rutherford Backscattering Spectrometry) technique. Optical characterisation was also performed and the photodegradation activity in the visible range was tested.