| Because TiO2 has a large forbidden band width,photogenerated carriers are easy to recombine,and easy agglomeration in practical applications restricts its wide application.In this paper,the TiO2 nanopowders were synthesized by hydrothermal method,and the effects of different hydrothermal conditions on the morphology and catalytic properties of TiO2 were investigated.The modification of rare earth lanthanum and silicotungstic acid was studied by rare earth lanthanum and silicotungstic acid modified TiO2.The effects of crystal structure,spectral absorption and photocatalytic properties of TiO2;the photocatalytic performance of methyl orange solution degradation system was evaluated.The results are as follows:The TiO2 nanopowders were prepared by hydrothermal method.The process parameters such as tetrabutyl titanate concentration,hydrothermal reaction time,hydrothermal reaction temperature,deionized water amount,calcination time and calcination temperature were studied to synthesize TiO2 nanopowders.The effect of catalytic performance.The results show that the prepared TiO2 is anatase-type,spindle-shaped particles with a long diameter of about 50 nm and a diameter of 10-30 nm.The photocatalytic performance is basically consistent with that of P25.On the basis of this research,the rare earth metal cerium doped TiO2 composite powder material was prepared by hydrothermal method.The doping of cerium ions causes the TiO2 lattice to be distorted,the average particle size decreases,the specific surface area increases,and the photocatalytic performance of TiO2 is also improved.When the La/Ti molar ratio is 1.25%,the degradation rate of methyl orange reaches 95.2%.Based on the doping of cerium ions,the La-TiO2 nanocomposites doped with cerium ions were surface-modified with silicotungstic acid.The modified nanocomposites La-TiO2/SiW]2 were prepared by impregnation method.The impregnation process and calcination were investigated.The effect of conditions on the spectral absorption and photocatalytic properties of the composite powder.The results show that when the impregnation concentration of silicotungstic acid is 0.04 mol/L and the calcination temperature is 400℃,the absorption intensity of the composite powder in the visible region is enhanced,and the degradation rate of methyl orange reaches 98%. |
