Preparation and Photocatalytic Activity of Boron or Zirconium Doped Titania

Effects of boron (B) or zirconium (Zr) doping on photocatalytic activity of sol-gel derived titania (TiO2) were investigated. Conventional, non-hydrous sol-gel technique was chosen to synthesize the B-Zr doped TiO2 powders. B and Zr doping was made separately at equivalent weight percentages (2.5 wt %) and compared to the undoped TiO2. Sol-gel derived xero-gels were calcined at 400, 500 and 600 °C after drying at 100 °C for 3 days. Particles in nano-scale (20-90 nm) were obtained after calcination at all temperatures. The crystal chemistry and the morphology of the undoped, B or Zr doped TiO2 nanoparticles were investigated using X-ray diffraction technique (XRD) and scanning electron microscope (SEM). Photocatalytic activity was measured through the degradation of methylene blue (MB) under one-hour UV-irradiation. Results revealed that the calcination temperature has a profound effect on the particle morphology and photocatalytic activity of TiO2. As the calcination temperature increased, rutile formation was favored in undoped state. But, anatase to rutile transformation was suppressed by both B or Zr doping into TiO2 and this effect was more remarkable as the calcination temperature was increased to 600 °C. Hence the photocatalytic activity of TiO2 increased by B or Zr doping. In addition, TiO2 nanoparticles tended to be more spherical by the temperature increase.