Study Of Effects Of La And Fe Doping For Structure And Property Of TiO₂ Photocatalyst

Titania is a n-type semiconductor, which can be used as photocatalyst. The ion-doping is an effective method to improve the photocatalytic activity. La,Fe and La/Fe doped titania were prepared by sol-gel method. The catalyst obtained were characterized by XRD,SEM, UV-Vis DRS, XPS. Their photocatalytic activities were investigated by photodegradation of methylene blue .It was concluded that La2O3 consisted in the grain boundaries of La-doped TiO₂. It could refine the grain, inhibit the phase transform from anatase to rutile and improve the transfer temperature. When the concentration of dopant was 0.5at% and sintered at 500℃,La-doped TiO₂ had the optimal photocatalytic activity. The photo degradation rate was 39.7% for methylene blue irradiated by xenon lamp for 3 hours.The band energy of TiO₂ decreased when it was doped with Fe. The absorption of light had a red shift to visible light region. It suggested that 0.5at% Fe doping increase the photocatalytic activity of TiO₂. The results showed that the optimal degradation rate for methylene blue can reach 56.4% using 0.5at% Fe doped TiO₂ calcined at 450℃.The co-doped TiO₂ with La and Fe had the optimal photocatalytic activity. The degradation rate for methylene blue could reach 84.6% when using the co-doped TiO₂ calcined at 600℃.