The Preparation Of Doped Nano-TIO₂ With Rare Earth Ions Ce～(3+),Y～(3+) And Their Photocatalytic Activities

In this paper, nano-TiO2 was prepared by the sol-gel processing. The influence of the calcined temperature, the ratio of H2O and Ti(Obu)4, the pH of sol and et al preparation parameters on photocatalytic ability of TiO2 were investigated. The sample was characterized by XRD, DRS and TEM to investigate the crystal form, diameter and the ability of light absorption. A 250W UV lamp (365nm) was used as side light source. The experiments of photocatalytic degradation of phenol were carried out in quartz glass tube. The optimizational design experiment was used to investigate the optimum preparation condition.Under the optimum preparating condition of nana-TiO2, the titanium nonopowders with doping of rare earth ion Ce3+ and Y3+ were prepared by the processing mentioned above. Thecompound samples were also characterized by XRD, DRS and TEM to investigate the influence of rare earth ions. The experiments of photocatalytic degradation of phenol were carried out to investigate the influence of different doped concentration of rare earth ions. The initiate pH of phenol and the light intensity also were investigated. The photodegradation and mineralization were confirmed by 721-spectrophotometer and COD measurements. The results:1. The optimum preparing parameters of preparing TiO2 were: ethanol as solvent, r=6.25, pH=2.5, T=400 C, t=5h.2. XRD showed both TiO2, Ce3+/TiO2and Y3+/TiO2 are mixture of anatase and rutile phase. The ratio of anatase and rutile was about 3:1.3. TEM showed that the diameter of pure TiO2 is about 31.15nm and doping can retard the development of TiO2 grain size. The diameter of Y3+/TiO2 is about 7nm~10nm, however the diameter of Ce3+/TiO2 is about 10~25nm. The quantum effect became more obviouser than pure TiO2 and the photocatalytic ability was improved.4. DRS showed that doping of Ce3+ and Y3+ could make the spectrum of TiO2 move towards the visible region, increase the light absorption ability of TiO2 and expand the excited range of TiO2. It made utilizing long wave light of solar light in photocatalytic degradation possible.5. The results of photocatalytic experiments showed: with the increase of dopant concentration, photocatalytic activity of TiO2 was improved significantly. As for doping Y3+, the optimum doping concentration was wt( Y3+) = 1.5%. As for doping Ce3+, the optimum content was wt(Ce3+) = 0.4%.The photocatalytic activity was about improved respectively 20% and 10% under the optimum doping concentration.