Photocatalytic Performance of Sn-Doped TiO2 Nanopowders for Photocatalytic Degradation of Methyl Orange Dye

The tin-doped TiO2 powders obtained by sol-gel and microwave-assisted sol-gel methods were investigated. The synthesis took place in a basic medium (pH 10, ammonium hydroxide, 25%) starting from tetrabutyl orthotitanate in its parental alcohol. In the case of the dopant, Tin(II) 2-ethylhexanoate as SnO2 precursor was used in the amount of 1, 2, or 4 mol % SnO2. Based on thermal analysis data, the powders were thermally treated in air, at 500 degrees C. The comparative investigation of the structure and morphology of the nanopowders annealed at 500 degrees C was performed by scanning electron microscopy (SEM), high-resolution transmission electron microscopy with selected area electron diffraction (HRTEM/SAED), scanning transmission electron microscopy (STEM) coupled with EDX mapping, Fourier transmission infrared (FTIR), UV-Vis, Raman and photoluminescence (PL) spectroscopy, X-ray diffraction (XRD), and X-ray florescence spectroscopy (XRF). The obtained materials were tested for the photocatalytic removal of methyl orange dye from aqueous solutions. High degradation efficiencies (around 90%) were obtained by Sn doping after 3 h of UV light irradiation.