Synthesis, Structural and Photocatalytic Behavior of Sn–F Co-Doped TiO2 Nanomaterials

Abstract

Sn–F co-doped TiO₂ nanomaterials were synthesized using the modified sol–gel method. The influence of different amounts of modifying agents (0.3–10 mol.% Sn⁴⁺ and 0.3–10 mol.% F⁻) and calcination temperature (500–800 °C) on the properties of the resulting nanomaterials was studied. Nanomaterials were analyzed using X-ray diffraction, high-resolution transmission electron microscopy, energy dispersive X-ray spectroscopy, selected area electron diffraction, differential scanning calorimetric and thermogravimetric analyses, UV–visible diffuse reflectance spectroscopy and other methods. It was found that the amounts of introduced Sn⁴⁺ and F⁻ ions and the temperature of the heat treatment regulate the phase composition and particle size of the resulting nanomaterials, as well as adjust the photocatalytic properties of the materials to be activated by UV and visible light. The materials are nanoscale, with an average size is 13–57 nm depending on the synthesis conditions. The best photocatalytic performance was observed for a material containing 0.3 mol.% Sn⁴⁺ and 0.6 mol.% F⁻. Co-doping of TiO₂ with F⁻ and Sn⁴⁺ ions significantly enhances the photocatalytic properties of TiO₂ in both visible and ultraviolet ranges, owing to a decrease in the band gap.