Study On The Preparation Of Co-doped Titanium Dioxide And Its Photocatalytic Property

Pure titania and nanoparticle titania co-doped with transition metal and rare earth metal were prepared by sol-gel method. The catalysts obtained were characterized by TG-DTA, XRD, TEM, DRS and XPS. Their photocatalytic activities were investigated by photocatalytic oxidation of methyl orange.The optimal molar ratio of tetrabutyl titanate, anhydrous alcohol, glacial acetic acid, and distilled water was 1:20:7:8, when TiO2 were prepared by means of sol-gel method. TiO2 prepared in the optimal ratio, sintered at 500℃for 2h, were totally anatase structure with 18.2nm of particle size, and the photocatalytic degradation efficiency was almost equal to P-25. The calcination temperature has notable effect on photocatalytic activity and crystal structure of TiO2. Four different sintering temperatures were selected in experiment. The result showed that the optimal temperature of heat treatment is 600℃; after TiO2 was calcined at 800℃, the formation of rutile phase appeared.The optimal co-doping amount (in molar ratio) for Fe-Ho and V-La was Fe:Ho:TiO2=0.05%:0.5%:1 and V:La:TiO2=0.05%:0.05%:1 respectively. The optimal temperature of heat treatment for Fe-Ho co-doped TiO2 and V-La co-doped TiO2 both were 600℃. The photocatalysis properties of TiO2 prepared under this condition can be enhanced largely than single metal doped TiO2 and undoped TiO2.The result of XRD showed that co-doping of Fe-Ho and co-doping of V-La both restrained the growth of the grains, promoted forming of nanoparticles and restrained the crystalline transformation of TiO2 from anatase to rutile. This effect was more obvious in Fe-Ho co-doped TiO2. The result of DRS showed that co-doping of Fe-Ho and co-doping of V-La both enhanced the spectrum absorption in ultraviolet light region and visible light region.Doped TiO2 catalyst supported on activated carbon fiber (ACF) were prepared by sol-gel method. The surface morphology, microstructure, specific surface area, D-TiO2 loading amount, photocatalytic activity and stability of D-TiO2/ACF were investigated by the techniques of SEM, BET, and photodegradation tests. The D-TiO2 /ACF exhibitited good photocatalytic activity for methyl orange and the activity kept little change during the course of reuse. The photocatalytic and adsorption performance can be enhanced by supporting TiO2 onto ACF.