Abstract:
Un-doped and doped TiO2 nanoparticles in the range 10-30 nm are synthesized via SolGel and Sol- hydrothermal routes. The obtained powders are characterized for their elemental phase analysis, particle size, structural morphology, and band gap studies by X-Ray Diffraction, Scanning Electron Microscopy and UV VIS spectroscopy. Addition of silver (Ag), zinc (Zn) and Ag-Zn impurities via in situ doping process is done to reduce the band gap of TiO2. The applications and unique properties of TiO2 depend upon the method of synthesis. Un-doped TiO2 nanoparticles were synthesized via Sol-Gel and Sol-hydrothermal routes by the reaction of titanium tetra chloride in acidic solution. HCl and NaOH/NH4OH are used as catalyst in the pH range of 2-13. In case of doped TiO2, the metallic solution of Ag or Zn or Ag-Zn was used in hydrolysis process with Ti- precursor. The XRD data shows that average crystallite size for hydrothermally treated doped/un-doped Titania samples remain in the range 10-12.9 nm while 20-30 nm for the samples via Sol-Gel route. It is observed via XRD results that we get mixed phases of anatase and rutile are obtained by Sol-Gel synthesized samples while only anatase phase stabilized in case of Sol-hydrothermal process. The EDX results indicated presence of titanium, oxygen and dopants in stoichiometric ratios. Due to small crystallite size the surface area of hydrothermally synthesized samples was high as compared to Sol-Gel. The SEM and showed that the particles have spherical morphology for sample obtained via Sol-hydrothermal route. UV-Vis measurements confirm the decrease in band gap of synthesized samples that is also higher in hydrothermally synthesized samples as compared to Sol-Gel.
