Study On The Structural And Electronic Properties Of Lanthanide-doped Nano-TiO₂

Heterogeneous photocatalysis based on semiconductor nano-oxides, is an ideal technology for remedying environmental pollution and has become one of the most active research fields in recent years. Titanium dioxide has been widely used as photocatalyst due to its nontoxic,high oxidation ability, good chemical stability and lost cost.In order to improve its photocatalytic ability and utilize solar energy more efficiently, titanium dioxide is doped with a variety of ions, especially lanthanide ions, which embodies unique 4f electronic configuration. Although there have been many reports on lanthanide-doped (hereafter abbreviated as Ln) titania, most of them deal with the degrading performance tests and the presented doping mechanism is based on hypothesis rather than science evidence. In essential, the electronic structure of titania is the predominant property which governs the photocatalytic ability. However, only a very limited research have been concentrated on this subject. Therefore, it is necessary to obtain the detailed information about the elecronic structures of Ln-doped titania.This thesis presents a study of structural, optical and electronic properties of Ln-doped titania. Based on First Principle, the band structures of Ln-doped titania are calculated and the model of electronic structure is also put forward. The emphasis is placed on the experimental and theoretical research of the electronic structure. Ln-doped titania are prepared using modified Sol-Gel method.The microstructure and morphology of the doped samples are characterized by using X-ray Diffraction (XRD), Infrared Spectrum (IR), X-ray photoelectron spectroscpy (XPS), transmission electron microscopy (TEM), high resolution TEM and energy...