A Comparative Study on the Structure and Photoactivity of Titanium Dioxide Obtained from Various Synthetics for the Degradation of Organic Dye

Titanium dioxide (TiO2) particles were synthesized by the sol-gel method (SG) and sol-gel low-temperature method (SG-L), utilizing titanium isopropoxide as the precursor. Subsequently, the particles underwent heat treatment with sodium hydroxide 10M, resulting in samples denoted as SG-H and SG-L-H samples, respectively. The purpose of this study is to compare these synthesis methods in terms of the stability and photocatalytic activity of TiO2 catalysts. To determine the optimal synthesis method for generating highly active TiO2, the obtained catalyst samples were characterized by a variety of techniques, including thermogravimetric analysis (TGA), differential scanning calorimetry (DSC), X-ray diffraction (XRD), Brunauer–Emmett–Teller (BET), and UV–vis spectroscopy measurements. The results demonstrated that the structure and phase of catalysts depend on the synthesis conditions. The surface area measurements indicated values of 0.95, 18.95, 82.65, and 168.59 m2/g for SG, SG-H, SG-L, and SG-L-H, respectively. Furthermore, the degradation efficiency of methylene blue under xenon lamp illumination was recorded at 87%, 91%, 97%, and 94% after 150 minutes, according to a pseudo-first-order reaction. These results suggest that the sol-gel low-temperature method is particularly effective in producing high purity, large specific surface area, and good decomposition of organic dye.