Structure Control of TiO_2 Nanotubes Having Mesopores on Their Tube Wall

通过将纯PVA纳米纤维浸渍在钛醇盐-乙醇溶液中形成PVA-Ti醇盐杂化前驱体纳米纤维。我们的方法很可能得到具有皮芯结构的前驱体聚乙烯醇，皮层是PVA-Ti醇盐杂化物，芯是纯PVA。前驱体纳米纤维经煅烧后易于形成TiO_2纳米管。纳米管的直径可以通过改变纯PVA微球的直径来控制。该方法制备的纳米管外径范围为300- 600 nm，具有较高的比表面积，氮气吸附等温线表明纳米管壁存在中孔。在400-600℃时，形成锐钛矿型TiO_2，峰强度随煅烧时间的延长而增强。在700℃以上形成金红石型TiO_2。以亚甲基蓝和乙醛的光催化降解为实验对象，研究了TiO_2纳米管的光催化性能。结果表明，纳米TiO_2的光催化性能优于市售的纳米TiO_2，具有上级的性能。

PVA-Ti alkoxide hybrid precursor nanofibers were formed by the immersion of pure PVA nanofibers in Ti alkoxide-ethanol solution. It is likely that a precursor nanofiber with a skin-core structure would be obtained by our method ; the skin layer is PVA-Ti alkoxide hybrid, and the core is pure PVA. TiO_2 nanotubes were easily formed by calcination of the precursor nanofibers. The diameter of the nanotube can be controlled by changing the diameter of the pure PVA nanofiber. The range of the outer diameter which can be formed in this study is 300-600nm.The nanotubes obtained had a high specific surface area and the existence of mesopores on the nanotube wall was indicated by the nitrogen adsorption isotherms. Anatase type TiO_2 was formed at 400-600℃, and the peak intensity increases with an increase in the calcination time. Rutile type TiO_2 was formed above 700℃. The photocatalysis of the TiO_2 nanotubes was evaluated using the photocatalytic decomposition of methylene blue and acetaldehyde. There were superior to the photocatalysis of commercially available anatase type TiO_2 nanoparticles.