Abstract: A polyacrylamide gel method was used to synthesize BaTiO₃ nanoparticles. X-ray diffraction, Fourier transform infrared spectroscopy, transmission electron microscopy, and ultraviolet-visible diffuse reflectance spectroscopy were adopted to characterize the sample. The results demonstrate that single-phase BaTiO₃ nanoparticles can be prepared at a calcination temperature of 700 ^oC when using citric acid as the chelating agent at pH = 2. The prepared particles are regularly shaped like spheres with an average particle size of ~55 nm and have an optical bandgap energy of 3.25 eV. The photocatalytic properties of BaTiO₃ nanoparticles were investigated using the degradation of the azo dye methyl red. The experimental results reveal that the nanoparticles exhibit a pronounced photocatalytic activity for the methyl red degradation under ultraviolet light irradiation, and the direct oxidation by the hole is suggested to be the main mechanism responsible for the dye decomposition.

Key words: barium titanate, nanoparticle, polyacrylamide gel method, photocatalysis, methyl red