N-doped Graphene/Titania Hybrid Materials,Preparation And Photocatalysis For Degradation Of Dye

In recent years, with the rapid development of the industrial technology of society, many people gradually pay attention to the problems of environmental pollution and energy shortage. Solar energy has the advantages of renewable, clean and cheap, therefore, how to use solar energy resource efficiently becomes the problem which people need to solve. Semiconductor photocatalytic degradation technology can translate the organic pollutants to harmless substance to the environment, and provide us with a green living space.In the semiconductor optical catalysts, titanuim oxide (TiO2) are widely used because of its high efficiency, no pollution and low price, etc. However, as photocatalyst, TiO2also has some disadvantages, for example, its wide band gap (3.2eV) leads that only the ultraviolet can meet requirement of the energy which is used to translate electron between the conduction band and valence band, so TiO2has a low utilization efficiency of sunlight and its potential practical applications has been limited, in addition, the photogenerated electron-hole pairs easily recombinated, which decrease the utilization rate of photoproduction carrier. Therefore, we want to make the photocatalytic efficiency of TiO2more outstanding through modification.Aiming at the shortcoming of the TiO2in performance, the main purpose of this study is to improve its photocatalytic activity by modified. In this experiment, we use the method of hydrothermal to synthysize nitrogen-doped graphene/TiO2photocatalyst (NGT), and then use the modified hybrid materials to degrade dye to test photocatalytic activity. The reason why we use graphene to modify the TiO2is that graphene has excellent electronic conductivity (15000cm2V-1s-1), which can make photocatalyst export electrons in a timely manner and reduce the recombination probability of electrons and holes, and it also has high specific surface area, which can be used to strengthen the absorption of composite materials. Through doping of nitrogen, the light absorption rang of photocatalyst can be extended to the visible light region, and its spectral response can be widened.Herein, the composites were characterized by X-ray photoelectron spectroscopy (XPS), transmission electron microscopy (TEM), UV-Vis Diffuse Reflectance Spectra (UV-Vis DRS), and power X-ray diffraction (XRD), et al. XPS results showed that N-doped graphene (NG) and N-doped graphene/TiO2(NGT) were successfully prepared, and the N atom%is3.50and2.09in the as-prepared NG and NGT, respecively. The UV-Vis DRS showed the band gap of materials, and NGT are2.04eV which indicated that the incorporation of NG into TiO2can reduce its band gap and extend the light absorption of NGT to the visible light region.Using above prepared composite materials as photocatalytic catalyty and eosin as organic pollutant, the photocatalytic degradation experiments were carried out under same conditions. We found that the different content of NG in hybrid materials lead to the different results of photodegradation, and the performance of nanocomposite photocatalysts is the best when its NG content is5%. Besides, the photodegradation performance of materials which did not be calcined is better than be calcined.