Narrow Results

Sn-doped TiO₂ nanomaterials were synthesized by sol–gel method. It was shown the phase compositions and phase transitions change with the introduction of different tin amounts (0.5–20mol.%). X-ray powder diffraction was used to study the effect of different tin amounts on the anatase–rutile phase transition. It was found that the introduction of ions increases the thermal stability of anatase modifications. The material’s photocatalytic activity was studied in reaction with a model pollutant (methylene blue) photodegradation under UV and visible light activation. The best photocatalytic properties were shown for material, which contains 5mol.% of Sn.

TiO₂ thin films were deposited on glass substrates by sol-gel method. Nanocrystalline TiO₂ thin films were prepared at ambient conditions and titanium tetraisopropoxide [C₁₂H₂₈O₄Ti] was used as a Ti-precursor. The effect of annealing temperature on optical properties of nanocrystalline TiO₂ thin films was studied. The as-deposited films were dried at 100 °C for 1 hr. The films formed were further heated in temperature between 200 and 500 °C for 1 hr. The films were characterized by different techniques: XRD, UV-visible spectroscopy, FTIR spectroscopy and FESEM. The characterization studies revealed that the films are crystallized as anatase phase and nano-structured with better optical properties α = 0.89 as compared to reported data. The optical measurement showed the indirect band gap between 3.31 and 3.35 eV with corresponding crystallite sizes between 8.9 and 3.7 nm. The FESEM image of film annealed at 400 °C showed spherical nanocrystalline structure of TiO₂ particles. The crystallite sizes obtained from FESEM image are found to be between 30 and 100 nm. It is also observed that refractive index of the film increases with increasing the annealing temperature. The smaller crystallite size gives larger band gap due to quantum size effects.