Well-aligned TiO2 nanorod arrays （TNAs） were prepared on pretreated quartz substrates via hydrothermal method.The effect of the different preparation conditions on the growth morphologies of TNAs was systematically investigated by X-ray diffraction （XRD） and field-emission scanning electron microscopy （FE-SEM）.The photocatalytic properties were tested by photodegradation of a methyl blue solution.It is demonstrated that the hydrothermal reaction conditions,such as precursor concentration,hydrothermal reaction temperature,and hydrothermal reaction times,can greatly affect the growth of TNAs.Controlling the preparation process,TNAs with 2 μm in length and 140-170 nm in diameter and well-aligned orientation have been successfully prepared.The photocatalytic experiment results indicate that TNAs have much better photocatalytic activity than TiO2 nanoparticles.
Well-aligned hexagonal ZnO nanotubes （NTs） arrays were synthesized on pretreated indium tin oxide （ITO） substrates by a simple hydro- thermal method. The morphology and structure of the products were characterized by scanning electron microscopy （SEM） and X-ray diffraction analysis （XRD）. A new method of substrate pretreatment was introduced to prepare ZnO coated films. The size of ZnO seeds and the formation rate of ZnO NTs were investigated. Further, the mechanism of the preparation of ZnO NTs was discussed. The photoluminescence （PL） spectrum measurement shows fairly internal defects existing in ZnO nanotubes.
Nano TiO2/Fe3O4 composite particles with different molar ratios of TiO2 to Fe3O4 were prepared via sol-gel method. X-ray diffraction, transmission electron microscopy, and vibration sample magnetometry were used to characterize the TiO2/Fe3O4 particles. The photocatalytic activity of the particles was tested by degrading methyl blue solution under UV illumination （254 nm）. The results indicate that with the content of TiO2 increasing, the photocatalytic activity of the composite particles enhances, while the magnetism of the particles decreases. When the molar ratio of TiO2 to Fe3O4 is about 8, both the photocatalytic activity and magnetism of the TiO2/Fe3O4 particles are relatively high, and their photocatalytic activity remains well after repeated use.
Well-aligned TiO2 nanorod arrays （TNAs） were prepared on the pretreated quartz substrates. The effect of the pretreatment conditions on the growth of TNAs was systematically investigated by X-ray diffraction （XRD）, field-emission scanning electron microscopy （FE-SEM） and high-resolution transmission electron microscopy （HRTEM）. It is demonstrated that the pre-coating TiO2 crystal seeds on the substrates can greatly improve the growth orientation of TNAs. Rutile Ti02 crystal seeds induce the nucleation and growth of TNAs more preferably than the anatase TiO2 seeds. The growth density and diameter distribution of TNAs strongly depend on the TiO2 crystal seeds density. It is proved that TNAs with different morphologies can be controllably synthesized by using hydrothermal approach by pretreating substrates. The photocatalytic activity of TNAs was investigated by measuring the photodegradation rate of methyl blue aqueous solution under UV irradiation （254 nm）. And the results show that TNAs with large growth density and small diameter size exhibit relatively higher photocatalytic activity.
