Investigation of photocatalytic activity of TiO2 nanoparticles synthesized by sol–gel technique

Anatase phase TiO2 nanoparticles were synthesized by sol–gel method using titanium(IV) butoxide as a starting material. The pH of solution was maintained by adding HNO3 and NaOH. The obtained powder was heat-treated at 350 °C for 2 h. The XRD study shows that the crystalline size and crystallinity of samples increase with pH of solution. Raman spectra confirm the dominance of anatase phase of TiO2. Morphology study of samples was done by scanning electron microscope (SEM). The size of prepared samples was calculated by XRD and confirmed by TEM analysis. The energy bandgap was calculated by optical absorption spectra and it was found to decrease by increasing pH of the solution. The photodegradation activity of Indigo Carmine (IC) dye under visible light irradiation was carried out by synthesized TiO2 nanoparticles. The removal of Indigo Carmine dye and degree of mineralization after photodegradation were studied using HPLC and TOC analysis respectively.