Photocatalytic degradation of an azo dye using N-doped NaTaO3 synthesized by one-step hydrothermal process

Abstract

N-doped NaTaO(3) compounds (NaTaO(3-)(x)N(x)) with nano-cubic morphology were successfully synthesized by one-step hydrothermal method and Methyl Orange (MO) was used as a model dye to evaluate their photocatalytic efficiency under visible-light irradiation. The as-prepared NaTaO(3-)(x)N(x) samples were characterized by various techniques, such as X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), scanning electron microscopy (SEM) and UV-vis diffuse reflectance spectra and GC-MS. The results indicate that NaTaO(3-)(x)N(x) displays a pure perovskite structure when the synthesis temperature is higher than 180°C. Moreover, as observed by SEM images, the particles of resultant NaTaO(3-)(x)N(x) show cubic morphology with the edge length of 200-500nm, which can be easily removed by filtration after photocatalytic reaction. Doping of N increases the photocatalytic activity of NaTaO(3), and NaTaO(2.953)N(0.047) shows the highest visible-light photocatalytic activity for the degradation of MO. Based on the experiment results, a possible mechanism of the photocatalysis over NaTaO(3-)(x)N(x) and the photodegradation pathway of MO were proposed.