| At present stage, environment crisis has become one of the main problems harm to people’s ecological balance. In recent years, photocatalytic technology was becoming a valid method to solve it, among that, TiO2 duo to its suitable price, easy preparation, stable physical and chemical properties and high catalytic efficiency has been the general concern of researchers. But it is well known that TiO2 (Eg)= 3.2 eV is wide bandgap semiconductor which can only use a fraction of the light of the sun, on the other hand, the light excitation of electron hole pairs are easy to composite, the two disadvantages of the TiO2 are reduced the catalytic efficiency of the photocatalyst. Therefore, there are two aspects can help us to solve the environmental crisis, firstly,we can look for a new photocatalyst, secondly we also can expand the light response area of catalyst has become a very meaningful study, it will be the key to effective utilization of solar energy. In this article, we use modified Hummer method to prepare the Graphite oxide (GO) poweder and it was restored by water and ethanol mixed solution. At the same time, the TiO2 Nanowire(NW) and TiO2 Nanospindle(NS) were prepared by hydrothermal method, then combine the commercial TiO2 (P25), NW, NS with graphene(GR). We get the P25-GR, NW-GR and NS-GR by hydrothermal method and the photocatalytic activity was evaluated by photodegradation of organic dye. At the last, we carry on the preliminary discussion about the influence of the form of TiO2 on light catalytic activity.The as-prepared composite was characterized by Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), photoluminescence spectrum (PL), scanning electron microscope (SEM), UV-vis absorption spectrum (UV-vis), transmission electron microscopy (TEM) and Raman spectrum(Rama). All of the results show that the size of NW is same, the external diameter about 10-20 nm, the length micron grade, and from the picture of TEM we can see the nanowires is solid, not nanotubes. The as-prepared anatase TiO2 displays exclusively a spindle-like nanostructure with a uniform size. More quantitatively, the diameters of 30-50 nm and the lengths of 100-200 nm for the nanospindles can be estimated from the TEM image. For the composites, the GO successfully reduced to the reduced graphene oxide and the TiO2 occupy most of the areas of GR.The prepared TiO2-GR nanocomposite has superior photocatalytic activity in the degradation test, showing an impressive photocatalytic enhancement over pure TiO2 which because graphene worked as the adsorbent and electron acceptor to efficiently enhance the dye photodecomposition. At the same time, the form of the TiO2 has a influence on the photocatalytic activity of composite. The NW-GR have a better activity which because NW have more uniform dispersion on graphene with less agglomeration. The NS-GR is better than P25-GR due to {001} facets of anatase TiO2 nanocrystals exhibit higher activities in photodegradation of organic pollutants.The main point of this article is concentrated in the preparation of different morphology and crystal structure of TiO2, and then combine with graphene to enhance and improve its photocatalytic performance. The reason is discussed to improve the performance of TiO2 catalyst, we also discuss about the change of the morphology and crystal structure plays roles on the compound photocatalytic performance, all of this can provides a new way to improve the catalytic activity of photocatalyst. |
PDF Full Text Request