Synthesis Of Bi₄Ti₃O₁₂ Nanorods Heterostructured And Their Photocatalytic Performance

Titanium dioxide(TiO2) is a low cost, non-toxic and characteristic of good chemical stability and catalytic activity material. Today, it has become one of the most widely used science materials. The one-dimensional titanium dioxide has a larger specific surface area for the chemical reaction to provide a contact area of more toxic, thus improving the reaction efficiency. However, due to TiO2itself is a wide band gap material, making it the main absorption of sunlight in the ultraviolet range, which greatly reduces the efficiency of light absorption. In the meanwhile, the rapid photo-recombination of electrons and holes will lead to low quantum long rate, thus making the photocatalytic efficiency poor. Bi4Ti3O12is a material with ferroelectric properties, while the ferroelectric has polarization reversal, electro-optical, thermal, piezoelectric, dielectric constant voltage adjustable properties. If we combine the ferroelectric and the semiconductor to form a heterojunction, it is most likely to produce superior performance, reducing TiO2itself larger band gap and suppressing internal TiO2re-composite carriers, then improving the photocatalytic of TiO2. In this article, the Bi4Ti3O12/TiO2heterojunction was prepared by the electrospinning and hydrothermal method. The main works are as follows:1. With the use of tetra-butyl, acetate, ethanol, PVP as the raw materials to formulated a light yellow precursor, TiO2nanorods were prepared by the method of electrostatic spinning. Final selection humidity40%under the conditions of voltage of12kV, the same sized nanorods can be prepared. Meanwhile, orderly nanotubes was prepared by anodic oxidation in an electrolyte solution of ammonium fluoride. This can be the basis for the preparation of the next heterojunction.2. Different concentrations of Bi4Ti3O12/TiO2heterojunction nanorods were prepared by the method of hydrothermal reaction with the TiO2nanorods. By X-ray diffraction(XRD), scanning electron microscopy(SEM), transmission electron microscopy(TEM), the as-prepared Bi4Ti3O12/TiO2heterojunction and TiO2nanorods were analyzed on the morphology and crystal structure.3. From UV-visible diffuse reflectance spectroscopy (UV-vis DRS) we can seen, compared to pure TiO2nanorods, the absorption band edge of Bi4Ti3O12/TiO2heterojunction has a slightly red-shift behavior and the band gap is also reduced, indicating the as-formed Bi4Ti3O12/TiO2heterojunction will help improve the absorption of visible light samples. Data conversion while calculating the direct band gap of the sample, it can be seen, with the increasing concentrations of the heterojunction, a direct band gap of the sample decreases. And elements Bi is helpful to improve the absorption efficiency of the sunlight sample.4. Photoluminescence spectra (PL) result show that, Bi4Ti3O12/TiO2heterojunction emission peak intensity at440nm was significantly reduced, indicating that the structure of the heterojunction between Bi4Ti3O12/TiO2effectively suppress light composite of electrons and holes. By photocatalytic degradation of methyl orange under UV shows this heterojunction ultraviolet radiation showed higher photocatalytic activity. And the conclusion has been arrived at that the heterojunction photocatalytic properties of heterostructures has significantly been improved with increase of the concentrations of heterojunction in the gradation of methyl orange experiment.