Photocatalytic Activity of TiO2 Synthesized by Sol-gel Method with Different Titanium Precursor: Impact of Doping Elements and Doping Ratio

Abstract

In this paper, with tetrabutyl titanate and isopropyl titanate as the titanium precursors, TiO2 nanoparticles doped with different amounts of N and V were synthesized using sol-gel method. The nanoparticles were mainly characterized by scanning electron microscope (SEM), X-ray diffraction (XRD), Ultraviolet-visible diffuse-reflectance spectroscopy (DRS) and the vis-photocatalytic activity was determined by measuring the rate of methylene blue decolorization. The results show that the grain size of TiO2 prepared by isopropyl titanate is smaller and the rutile transformation temperature is higher than that of tetrabutyl titanate. Furthermore, N-doping or V-doping greatly enhance the visible-light photocatalytic ability of TiO2 nanoparticles and when the mole fraction of Nitrogen is in the range of 15%-20%, the photocatalytic activity of the N-doped samples is the highest, for V-doped samples, the optimal mole fraction is 0.05%. Overall, we have identified that the photocatalytic ability of N-TiO2 is stronger than V-TiO2. Eventually, we draw the conclusion that modified TiO2 visible light catalytic ability is positively correlated with the visible absorption capacity and negatively correlated with grain size.