Study On Synthesis, Characterization And Performance Of Nano-scale Mesoporous TiO₂

In this article, nano-scale mesoporous TiO₂ with high photocatalytic activity was prepared by the normal temperature hydrolysis. Hexadecyltrimethylammonium romide(CTAB) as template,Ti(OC4H9)4 as predecessor and ethanol as solvent. Experiments decided on synthesis condition of nano-scale mesoporous TiO₂ through investigating calcined temperature,calcined time,reactants ratio,ect.Then, metal ions Ce³⁺,La³⁺ ,Sm³⁺ and Zr³⁺was added the mesoporous system to synthesize mesoporous composite respectively.The resulting products were methodically characterized by FT-IR,XRD,BET and TG methods.The results showed that these materials possess mesoporous structure. The pure products are the type of anatase after calcined at 500℃for 2h,all templates are removed completely,and possess high surface area,but are much less stable. Based on all conditions,samples doped by Zr³⁺,Sm³⁺ and La³⁺ are composed of not only anatase but also a little of brookite; sample doped by Ce³⁺ is single anatase.Metal ions doped nano-scale mesoporous TiO₂ have different crystal degree of anatase.There are small amount of templates in the mesopores of TiO₂.Surface area is higher than pure nano-scale mesoporous TiO₂ after calcination,and more stable.We evaluated photocatalytic activity of nano-scale mesoporous TiO₂ and TiO₂ composite oxides by using methyl orange as the objective degrading substance. The results showed that the technology condition for synthesising the product with best photocatalytic activity is CTAB/Ti(OC₄H₉)₄(molar ratio):1:4, standstill temperature: 20℃, standstill time:24h, calcination temperature:500℃,,calcinations time:2h. There was an optimum ion doping amount for degradation of methyl orange,and different metal ions doped nano-scale mesoporous TiO₂ have different photocatalytic activity,the orders of the photocatalytic activity are as follows:Zr³⁺- TiO₂>Sm³⁺-TiO₂>m-TiO₂>La³⁺-TiO₂>Ce³⁺-TiO₂>c-TiO₂...