Preparations And Properties Of TiO₂ And ZnO Multilevel Structure With Special Morphology

The physical and chemical properties of nanomaterials are greatly affected by their morphology and structure.The 3D multilevel structure nanomaterials with special morphology have become the research focus in the preparation of nanomaterials.As two typical n-type wide band gap semiconductor materials,TiO2 and ZnO have excellent electrical,optical and catalytic properties,and have been widely used in photocatalysis and gas sensors.TiO2 and ZnO nanomaterials with 3D special morphology were prepared by hydrothermal method,and their applications in photocatalysis and gas sensor were studied.The main contents and results of this paper are as follows:(1)Using tetrabutyl titanate as the Ti source,HCl is used as an acid medium solution,under the hydrothermal conditions of no template,no additive and no seed,rutile 3D tree-like TiO2(TiO2-TLs)nanostructures self-assembled from 1D nanorods were prepared by one-step method.The TiO2-TLs nanostructures are self-assembled from the branch nanorods with the main exposed(101)and(111)surfaces along two low energy(110)and(101)surfaces of the trunk nanorods.Under UV irradiation,the degradation rate of RhB by TiO2-TLs as photocatalyst is 2.5 times and 1.5 times higher than that of rutile TiO2 common powder and TiO2-RLs,respectively.The gas sensor based on TiO2-TLs has good selection and stability to CH3COCH3 gas,and the sensitivity is about 10.4 at the optimum voltage,which is about 2.7 times and 1.5 times as much as that of rutile TiO2 common powder and TiO2-RLs gas sensor,respectively.(2)A novel porous 3D cage-like ZnO(ZnO-CLs)were prepared on ITO by hydrothermal method combined with anhydrous ethanol solvent and Zn(NO3)2.Because of the special structure characteristics of porous 3D,the degradation rate of RhB by ZnO-CLs is twice as high as that of common ZnO powder.ZnO-CLs also has good photodegradation activity to MO and MB.The gas sensor based on ZnO-CLs has good selection and stability to CH3COCH3 gas.Under the optimum voltage,the sensitivity to 100 ppm acetone gas is about 48,which is about 11 times of that of the ordinary ZnO powder.(3)The 3D multistage flower-like ZnO(ZnO-FLs)self-assembled from.porous wafers based on gas-sensing ceramic tubes and FTO was grown by hydrothermal method combined with H2O solvent and Zn(NO3)2.The sensitivity of gas sensitive components made directly from gas sensitive ceramic tubes grown with ZnO-FLs to CH3COCH3 gas is 6.2 times and 1.4 times higher than that of common ZnO powder and ZnO-FLs gas sensitive components made by traditional coating method,respectively.(4)Using AgNO3 as Ag source,Ag were successfully modified on the surface of TiO2-TLs and ZnO-CLs by UV in-situ reduction method.Ag@TiO2-TLs and Ag@ZnO-CLs composite nanomaterials were obtained.The Au were successfully modified on the surface of TiO2-TLs and ZnO-CLs by ion sputtering method.Ag@TiO2-TLs and Ag@ZnO-CLs composite nanomaterials were obtained.Ag@TiO2-TLs、Ag@ZnO-CLs、Au@TiO2-TLs、Au@ZnO-CLs enhances UV-Vis absorption,and has better photodegradation activity than pure TiO2-TLs and pure ZnO-CLs.