| 초록 |
It is well known that nitrogen and sulfur codoped TiO2 has high photocatalytic activity under visible light irradiation. In this study, nitrogen and sulfur codoped TiO2 (NST) was fabricated by solvothermal method, and the effect of thermal treatment on the photocatalytic activity of NST was investigated. Crystallization of NST and formation of the anatase phase were observed by X-ray diffraction (XRD) spectra, differential scanning calorimetry (DSC), thermogravimetric analysis (TGA), and high resolution-transmittance electron microscopy (HR-TEM). X-ray photoelectron spectroscopy (XPS) analysis indicated that nitrogen and sulfur atoms are doped at oxygen site of TiO2. The contents of nitrogen atoms are significantly decreased with crystallization of NST. As the thermal treatment progressed, sulfur atoms move from the oxygen site to surface of NST and finally form sulfate at the surface. However, total amount of sulfur in NST is maintained. UV-Vis diffuse reflectance spectroscopy (DRS) reveals that absorbance of visible light is dependent on quantity of nitrogen atoms. The photocatalytic activities of NST were evaluated by the degradation of rhodamine B under visible light irradiation. NST, which was treated at low temperature, has high photocatalytic activity. This result shows that TiO2 with high contents of dopants at oxygen site has high photocatalytic activity under visible light irradiation. |
