Influences of Rare-earth Ions Doping on the Structure and Photocatalytic Activity of TiO2

Rare-earth (RE)-doped TiO2 photocatalysts were prepared by doping samarium ions into TiO2 nanoparticles in a sot-gel process. The samples were characterized using X-ray diffraction (XRD). Their photocatalytic activities were evaluated by photodegradation of methyl orange (MO) in water under UV light irradiation. Finally, influences of rare-earth ions doping on the structure and photocatalytic activity of TiO2 were studied using grey correlation analysis method based on multi-variable grey model. The experimental results indicated that the doping modifications of TiO2 work through the structure change in nanoscale, leading to the change of activities. It was also found that the main actors influencing on activity of RE-doped TiO2 are crystalline size (D) and crystal constant (a) for the MO photodegradation base on the grey relational analysis method. Using the same method above, the activities of RE-doped TiO2 photocatalysts could be predicted and doping concentration need to be optimized.