Synthesis, characterization and photocatalytic applications of Zn-doped TiO2 nanoparticles by sol-gel method

Mesoporous, nanocrystalline, Zinc-doped TiO2 nanoparticles were synthesized by surfactant-assisted solgel method. The X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), Brunauer-Emmett-Teller (BET), and UV-VIS spectrometer techniques were used to characterize the synthesized products. XRD results confirm the formation of the anatase phase for the TiO2 nanoparticles, with crystallite sizes in the range of 12.6-18.1 nm. The small crystallite size and doping with Zinc ion inhibit phase transformation and promote the growth of the TiO2 anatase phase. The SEM and TEM micrographs revealed the spherical-like morphology with average diameter of about 12-18 nm which is in agreement with XRD results. The optical study shows that doping ions lead to an increase in the absorption edge wavelength and a decrease in the band gap energy of titania. Photocatalytic activity of the synthesized nanomaterials was successfully tested for photodegradation of methyl red as model pollutant under UV light. The photocatalytic activity results confirm that the doped nanoparticles show higher activity than undoped titania. The small grain size, high crystallinity, high specific surface area and decrease in the band gap energy of doped titania may be responsible for the high photocatalytic activity.