The Research Of Doping Modification Of TiO₂

Looking at new and original solutions to treat environmental pollution problems and the continuous increasing demand of energy, in the recent years a lot of attention have been devoted to TiO2photocatalysts due to its non-toxicity, easy-synthesis, long-term stability, high efficiency and low cost. However, its limited range of response in the ultraviolet actually limits large-scale industrial applications. Since2001, many studies devoted to the metallic and non-metallic ion doping of titanium dioxide to improve its photocatalytic activity, achieved stimulating results.The main contributions of this thesis are:1. For Fe-doped TiO2samples, we found that substitutional Fe atoms lead to the formation of structural defects with the appearance of new intermediate energy levels. This mechanism narrows the band gap and extends the optical absorption edge towards the visible region.2. For N-doped TiO2samples, we found that doping nitrogen atoms form an interstitial pattern in the crystal lattice of the titanium dioxide, reducing its phase transition temperature. Moreover, the2p state of N and O may form a mixed state that leads also to the narrowing of the band gap with an enhancement of the photocatalytic activity of doped samples.