小粒径锐钛矿/金红石混相TiO2的可控合成及光催化性能研究

本文利用水热法成功合成了小粒径（~ 5 nm）锐钛矿/金红石混相TiO2，通过XRD，TEM表征研究了水热反应前的熟化温度和熟化时间对TiO2的晶相、相组成和颗粒尺寸的影响。我们发现通过简单地改变熟化温度及时间能够可控调节样品中锐钛矿与金红石的含量。更重要的是，合成的混相TiO2样品中，锐钛矿与金红石的粒径都很小。以对罗丹明B的光催化降解为目标反应，评价混相TiO2粉体的光催化活性。通过表面光电压谱的分析可以发现，TiO2样品中锐钛矿与金红石异相结的形成增强了光生电子与空穴的分离效率，从而使混相样品的光催化活性明显优于纯相锐钛矿。此外，我们发现，锐钛矿含量为83%、金红石含量17%的TiO2样品展现了最高的光催化活性。

Controllable synthesis of mixed phases TiO2 with small anatase and rutile particle and its enhanced photocatalytic activity

Mixed phase TiO2 photocatalysts with small particle size of anatase and rutile (~ 5 nm) have been successfully synthesized using hydrothermal method. The effects of curing temperature and curing time before hydrothermal on the crystalline phase, phase composition, and particle size of TiO2 were investigated by X-ray diffraction spectroscopy (XRD) and transmission electron microscopy (TEM), respectively. It is found that the anatase and rutile phase contents in the TiO2 particles were successfully controlled by simply adjusting the curing temperature and time. More importantly, the particle size of both anatase and rutile is small in the TiO2 particles with mixed phases. The photocatalytic activities of the TiO2 were evaluated by the degradation of Rhodamine B (RhB) in aqueous solutions. The TiO2 with phase junction formed by anatase and rutile exhibited higher separation rate between photoinduced electron and hole, which was confirmed by surface photovoltage (SPV) spectra, and then exhibited the higher photocatalytic degradation on RhB than pure anatase phase TiO2. Moreover, it is found that TiO2 with 83% anatase and 17% rutile shows the highest photocatalytic activity among the TiO2 samples with mixed phases.