Preparation And Photocatalytic Properties Of Controllable Morphology Nano-TiO₂

It has gradually become an industrialized technology to use Nano-TiO₂ photocatalysis material for the photocatalysis degradation of the organic pollution.This technology represents wide prospect on the treatment of the pollution from the soil,water and aerosphere. The present advance of photocatalytic technology and the mechanism of photocatalytic reaction and recent preparation methods of photocatalytic material were summarized.The nano-TiO₂ with special morphology was prepared.The primary factors effecting the photocatalytic activity and typical preparation method of nano-TiO₂ were discussed.The morphology of the samples was studied by TEM and SEM.The phase and component of the of the samples was analyzed by XRD and FTIR.The photocatalytic properties of the samples were evaluated using their degradation of the methyl orange under the irradiation of ultraviolet radiation.The content of the text was as follows:(1) Nano-TiO₂ powder was obtained by sol-gel method.The dosage of the de-ionized water,the solvent(absolute ethyl alcohol),the chelating agent(acetylacetone) was determined. The effect of reaction temperature on the gel time and the photocatalytic properties was also considered to obtain the optimum craft for the samples.The optimum volume ratio of TBOT, absolute ethyl alcohol,de-ionized water,hydrogen nitrate and acetylacetone was 1:7:0.7:0.1:0.15.The optimum reaction temperature was 25-30℃.Combing the effect of reaction and calcination temperature,the dosage of nano-TiO₂ on the photocatalytic efficiency, the optimum degradation condition was fixed.The optimum temperature and time for the calcination were 600℃and 2h respectively,the optimum dosage of nano-TiO₂ was 3g/L.(2) The porous nano-TiO₂ powder was obtained using organic template by sol-gel method,and the mechanism was discussed.Tween-60,Polyethylene glycol(4000),and glycerin monostearate were used as template to obtain porous nano-TiO₂.The diameter of the powder was between 10nm and 30nm.The diameter of the porous structure was between 20nm and 30nm.Through the discussion of the effect of the dosage of the template on the degradation efficiency of methyl orange,it can be found that the photocatalytic properties was maximum when the dosage of tween-60,polyethylene glycol(4000),and glycerin monostearate were 0.3005g,0.0841g and 1.6mL respectively.The photocatalytic efficiency was 82.7%86.6%90.3%accordingly,and were improved by 15%-22%.The samples also have high photocatalytic activity after regenerating,the photocatalytic efficiency was 80.8%85.6% 88.4%.(3) The porous microtubular nano-TiO₂ was obtained using degreasing cotton template by sol-gel method.The diameter of the tubular nano-TiO₂ was between 3μm and 5μm.The wall thickness was 100nm.The degradation efficiency of methyl orange was up to 80.3%within 150min.The samples also have high photocatalytic activity after regenerating, the photocatalytic efficiency was 76.8%.The photocatalytic properties and the formation mechanism of the microtubular were discussed.(4) Based on the optimum craft of the microtubular,ferric nitrate was used as doped agent to obtain band-like nano-TiO₂.The width of the band was 5-8μm,and the thickness was 100-500nm.It is found that the degradation efficiency of methyl orange was maximum as the doped amount was 0.04%.The degradation efficiency of methyl orange was up to 92.3% within 150min.The samples also have high photocatalytic activity after regenerating,the photocatalytic efficiency was 90.1%.The influnce of the doped amount on the structure and photocatalytic properties of the samples and the formation mechanism of the band-like nano-TiO₂ were given a detail analysis.