Photocatalytic Activity of Visible-light-driven Zirconium Doped TiO2 Photocatalysts

TiO2 photocatalysts doped by different contents of zirconium ions were prepared by a sol-gel method. The experiments of 4-chlorophenol photocatalytic degradation showed that the TiO2 with zirconium doped content at 10% exhibited the best photocatalytic activity. Its photocatalytic efficiency is 1.5 and 4 times as high as that of pure TiO2 under ultraviolet and visible light. The samples were characterized by XRD, XPS, UV-Vis diffuse reflectance absorption spectra and photo luminescence. It was revealed that zirconium ions substituted the lattice titanium ions in TiO2 lattice. And thus, the doping energy level attributed to the zirconium dopant was located at 0.3 eV below the conduction band of TiO2, which enhanced the response to the visible light and accelerated the separation of photogenerated carries. In addition, more surface defects and hydroxyls were present on the surface of zirconium doped TiO2. Consequently, the zirconium doped TiO2 showed improved photocatalytic activity for photodegradation of 4-chlorophenol compared to pure TiO2 under both UV and visible light irradiation.