TiO2纳米管的制备及其光电性能研究

Preparation and Photoelectric Properties of TiO_(2)Nanotubes

采用水热法成功地制备了厚度为1 nm,直径为15 nm的TiO_(2)纳米管。利用差热-热重分析、X射线衍射、透射电镜及紫外-可见漫反射光谱对产物的结构进行了表征,并通过TiO_(2)纳米管对甲基橙的降解效果对其光催化活性进行评价。结果表明:制备的TiO_(2)纳米管有锐钛矿和金红石两种晶型,反应时间对样品的组织结构和光催化活性有较大影响,金红石相比例随着反应时间的增长而减少。反应时间为12 h时,TiO_(2)纳米管具有更佳的晶型比例及形貌结构,光催化性能最好。通过对TiO_(2)纳米管的形成机理研究发现:TiO_(2)前驱体先在强碱的作用下形成片状结构的碱金属钛盐,然后,该片状结构在表面静电作用和弹性形变等多因素诱导下转变成更稳定的纳米管状结构。

TiO_(2)nanotubes with a thickness of 1 nm and a diameter of 15 nm were successfully prepared by hydrothermal method.The structure of the product was characterized by differential thermogravimetric analysis,X-ray diffraction,transmission electron microscopy and UV-Vis diffuse reflection spectroscopy.The photocatalytic activity of the product was evaluated by the degradation effect of TiO_(2)nanotubes on methyl orange.The results show that the synthesized TiO_(2)nanotubes have two crystal forms:anatase and rutile.The reaction time has a great effect on the structure and photocatalytic activity of the samples,and the ratio of rutile decreases with the increase of reaction time.When the reaction time was 12 h,the photocatalytic activity of TiO_(2)nanotubes was the best because of its better crystal structure and morphology.The formation mechanism of TiO_(2)nanotubes was studied.It was found that the precursor of TiO_(2)was formed under the action of strong alkali.Then,the lamellar structure is changed into a more stable nanotube structure induced by many factors such as surface electrostatic action and elastic deformation.