Study On Synthesis And Photocatalytic Properties Of Fe-Doped TiO₂ Nanotubes

The different contents of Fe-doped titania nanopowders were prepared and sintered in oxidizing and reducing atmospheres, then the hydrothermal method was adopted to fabricate the titania nanotubes. Moreover, the prepared nanotubes were further sintered in a reducing atmosphere. The effects of sintering atmosphere, iron content and the reducing atmosphere on the photocatalytic properties of the nanotubes were studied in this paper. The nanotubes were characterized by TEM and XRD methods and the photocatalysis performance of nanotubes were studied by using the UV-methylene blue solution system. The results of the study are shown as follows.The phase of the titania nanotubes is mainly affected by the precursor. The Fe content in titania powders can effectively inhibit the phase transformation of rutile. Meanwhile, with the increase of iron content, the inhibition effect of the phase transformation and the anatase size increased. And reducing sintering of precursor introduces more oxygen vacancies to weaken the inhibition effect of rutile transformation. The aspect ratio of the Ti O₂ nanotubes decreases with the iron ion content of precursors increased. Sintering in reduction also reduces length-diameter ratios of Ti O₂ nanotubes. Sintering below 400 ℃ in a reducing atmosphere does not affect the phase transformation. But at 400 ℃, the structure of nanotubes was damaged and become granular, which have serious aggregation behavior. The titania nanotubes grow along the [100] direction and roll up in the（200） plan which consistent with the curl forming theory. Fe-doping and reducing sintering atmosphere do not affect the growth direction of the nanotubes. The titania nanotubes doped with 1mol % of Fe and sintered at 200℃ in reducing atmosphere have the best photocatalytic performance such as 98%. It was also found that the amount of degradation of titania nanotubes sintered in reduction atmosphere increases obviously. Adsorption of a large number of the methylene blue on the titania nanotubes makes them lost the degradation activity.