Study On Modification Of Nitrogen, Phosphorus Doped Titanium Dioxide Photocatalyst

Photocatalysis has caused high concern because it can degrade environment contaminants effectively. Among various photocatalysts, TiO2 nanoparticles have received great attention due to their potential function for decomposition various toxic gases and oxidation various organic compounds, such as harmful dioxins, into harmless compounds by irradiation with UV light. However, TiO2 could only be activated by UV light because of its large band gap and this poses a great barrier to the wide application of TiO2. Happily, there are a number of empirical ways to sensitize TiO2 to a much larger region, for instance, metal doping and non-metal doping, and non-metal doped TiO2 can commonly extends the range of absorption to light and improve the capability to visible light, such as C, N, F, S, P doping. In this paper, we made nitrogen, phosphorus and sulfur doped in TiO2 to improve its photocatalytic activity.P-doped titania was synthesized by a one step hydrothermal method and sol-gel method, which is characterized by X-ray diffraction (XRD) and X-ray photoelectron spectroscopy (XPS). Compared to those prepared by conventional calcination method, the samples prepared by hydrothermal method demonstrate higher photocatalytic activity toward the degradation of methylene blue under xenon lamp which has similar spectra to solar light. The as prepared P-doped titania shows a small particle size (the minimum reaches to 4.5 nm). In addition, the samples prepared by hydrothermal treatment could obtain more tetrahedron structure in the crystal lattice, which could result in a lots of oxygen vacancies, and it is account for the samples synthesized by hydrothermal method performs a better photocatalytic activity. However, P-doped titania can further enhacnce the photocatalytic activity effectively, and hydrothermal treatment is a very suitable method for the synthesis of P-doped titania. This excellent performance could endow the as-prepared P-doped titania potential in purifying wastewater.N-doped, N, P-codoped and N, S-codoped TiO2 were prepared by hydrothermal method, which is characterized by X-ray diffraction (XRD) and X-ray photoelectron spectroscopy (XPS). The photocatalytic activity of them was evaluated for the degradation of methylene blue under xenon lamp which has similar spectra to solar light. The results domenstrated that the N, P-codoped TiO2 powders exhibited a better photocatalytic activity, and the optimum molar ratio is also investigated. By analyzing the XPS, we found that PO43- could as one unit to participate the formation of the crystal lattice, in which case it may lead to a distorted crystal lattice structure which contain more oxygen vacancies or defects. Therefore, N, P-codoped TiO2 performs a better photocatalytic activity.