Heat-assisted sol–gel synthesis of tio₂ nanoparticles structural, morphological and optical analysis for self-cleaning application

This study synthesized TiO₂ nanoparticles using the sol–gel method assisted by heat from Titanium (IV) Isopropoxide. Samples were calcined at 400, 600, and 800 °C, and studied for self-cleaning application. The nanoparticles were characterized using X-ray diffraction (XRD), Scanning electron microscopy (SEM), transmission electron microscopy (TEM), Raman spectroscopy, and UV–vis spectroscopy. A self-cleaning application test was also performed using methylene blue dye as a form of contaminant. The TiO₂ nanoparticles showed improved crystallinity with increased calcination temperature and experienced a phase transformation from anatase to rutile after 800 °C calcination. Crystallite size ranged from 5.11 to 24.97 nm for anatase and 15.85 to 24.72 nm for the rutile from the XRD result. Raman spectra showed increased peak intensities with an increase in calcination temperature. The grain size distribution from TEM analysis revealed the particle size with the uniform count at 400 °C and 800 °C than at 600 °C. The bandgap for direct transition was evaluated to be 3.07 eV. The self-cleaning test confirmed that the TiO₂ nanoparticles would be effective in self-cleaning applications. The sample that was calcined at 600 °C displayed the highest self-cleaning ability.