Effect of annealing on sol-gel derived TiO2 nanoparticles in acidic medium

TiO2 nanoparticles are prepared by sol-gel method. As revealed by X-ray diffraction (XRD) spectra the nanoparticles change their phase from anatase to rutile when the annealing temperature goes beyond 650°C. W-H plot for the powder samples annealed at 450°C and 750°C shows the presence of tensile strain in them which affects the particle size. The difference in particle sizes obtained from Debye-Scherer formula and W-H plot is seen to reduce for lesser strain value. The field emission scanning electron microscope (FESEM) images are observed to depict the agglomerated clusters of the particles whose average size favors the XRD results. The absorption is seen to show a red shift, as annealing temperature is raised.