Preparation and Characterization of TiO 2 Nanotube Arrays with Short Tube Length and Its Photocatalytic Degradation of Organic Pollutants

In this study, highly ordered TiO2 nanotube arrays (TNAs) with length 1~2 μm were rapidly fabricated via the electrochemical anodic oxidation process, which was specifically used for the photocatalytic degradation of organic pollutants. The effects of the anodization conditions on the nanotube microstructures were investigated with scanning electron microscope (SEM). The crystalline phase and surface element of the as-prepared samples were characterized by X-ray diffraction (XRD) and X-ray photoelectron spectroscopy (XPS), respectively. On this basis, the effects of TNAs morphological parameters on the photocatalytic activity were evaluated by the degradation of rhodamine B (RhB) in aqueous solution. The results showed that the diameter and length of the nanotube were linearly related to the anodization voltage in the experimental ranges with 20 wt% water content electrolytes, respectively; the morphological parameter and anodization time were also linearly related. TNAs calcined at 450 °C for 2 h were pure anatase phase and contained Ti3+ element, which were favorable for the photocatalytic reaction. In the study, it was proved that 20 wt% water content electrolytes were suitable for the rapid anodization generating of TNAs with the length 1~2 μm. The assessment experiments for the photocatalytic activity of TNAs demonstrated that, when the actual tube length was near the penetration depth of UV lights, TNAs would exhibit the best photocatalytic activity.