Synthesis, characterization and application of undoped TiO₂ and co-doped TiO₂ (with Ba & Co) for the photocatalytic degradation of Coomassive brilliant blue (CBB) dye under UV light irradiation

Titanium oxide (TiO₂) and Ba and Co co-doped TiO₂ nanoparticles were synthesized through a sol-gel method. The synthesized nanoparticles were characterized using X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), UV-visible spectroscopy (UV-Vis), and scanning electron microscopy (SEM). Using X-ray diffraction analysis different parameters were calculated, such as crystallite size, d-spacing, dislocation density, number of unit cells, cell volume, morphological index, microstrain and instrumental broadening. The average particle size of both titanium oxide (TiO₂) and Ba and Co co-doped TiO₂ nanoparticles was calculated to be 15.98 nm and 24.69 nm, respectively. Scanning electron microscopy revealed that TiO2 has rough spherical morphology with small particles agglomeration while Ba and Co co-doped TiO₂ nanoparticles consist of slightly larger blocks of agglomerated particles with irregular morphology. Doping of TiO₂ with Ba and Co decreased the band gap from 3.10 eV to 2.92 eV. The characterized particles were used as a photocatalyst for the degradation of Coomassive brilliant blue dye in aqueous solution under UV light. The effect of different parameters, e. g. irradiation time, initial dye concentration, pH of the medium and catalyst dosage on the percent degradation was also studied. The dye degradation linearly increased with an increase in irradiation time. About 93% and 77% dye degradation was observed at 240 min duration using undoped and Co-Ba-doped TiO₂, respectively. The degradation of the dye was found to decrease with an increase in initial dye concentration. On increasing the amount of Co-Ba-doped TiO₂ catalyst the rate of degradation increased while using bare TiO₂ the percent degradation decreased with increase in catalyst dose up to 0.05 g. At low pH higher degradation was found as compared to higher pH. Co and Ba co-doped TiO₂ powders exhibited high photocatalytic activity towards discoloration of Coomassive brilliant blue dye.