A polyacrylamide gel route to different-sized CaTiO3 nanoparticles and their photocatalytic activity for dye degradation

Calcium titanate (CaTiO3) nanoparticles with different average sizes were prepared by a polyacrylamide gel route, where the particle size was tailored by using different chelating agents. Scanning electron microscope observation shows that the samples prepared by using the chelating agents EDTA, acetic acid, tartaric acid, and citric acid have an average particle size of 25, 33, 36, and 55 nm, respectively. All the particles are regularly shaped like spheres. The bandgap energy of the four samples is measured to be 3.66-3.59 eV by ultraviolet (UV)-visible diffuse reflectance spectroscopy. The photocatalytic activity of the prepared CaTiO3 samples was evaluated by the degradation of methyl orange under 254 nm UV irradiation, revealing that they exhibit a good photocatalytic activity. Hydroxyl radicals are revealed, by the photoluminescence technique using terephthalic acid as a probe molecule, to be produced on the irradiated CaTiO3 nanoparticles and suggested to be the primary active species toward the dye degradation.