Narrow Results

Pure titania (TiO₂) nanopowders and TiO₂ doped with 10 mol % of vanadium ions (V³⁺) are synthesized by sol-gel method. The dependence of structural characteristics of nanopowders on synthesis conditions is investigated by X-ray diffraction and Raman spectroscopy. Very intensive modes observed in Raman spectra of all nanopowders are assigned to anatase phase of TiO₂. Additional Raman modes of extremely low intensity which can be related to the presence of small amount of brookite amorphous phase are observed in pure TiO₂ nanopowders. In V-doped nanopowders anatase was the only TiO₂ phase detected. The variations in duration and heating rate of calcination influence slightly the Raman spectra of pure TiO₂, but have a great impact on Raman modes of anatase, as well as the additional Raman modes related to the presence of vanadium oxides in V-doped samples.