Visible light induced photocatalytic degradation of direct red 23 and direct brown 166 by InVO4-TiO2 nanocomposite

The effect of various parameters (pH, irradiation time, nanophotocatalyst dosages and temperature) on photocatalytic degradation of Direct Red 23 (DR 23) and Direct Brown 166 (DB 166) using pure InVO4 and InVO4-TiO2 nanocomposite were investigated under visible light irradiation. InVO4 and InVO4-TiO2 were synthesized by hydrothermal and sol-gel/ hydrothermal treatment techniques, respectively and characterized by FT-IR spectroscopy, x-ray diffraction (XRD), diffuse reflectance UV–vis spectroscopy (DRS), scanning electron microscopy (SEM) and transmission electron microscopy (TEM) images. Doping of TiO2 with InVO4 caused reduction in its band gap value with the resultant improvement in its visible light activity. The efficiency of nanocomposite on azo dyes degradation (pH 7.2, time: 30 min) reached high values (above 95%) under visible light, proving the remarkable photocatalytic activities of obtained composites. Moreover, the results indicated complete mineralization of DR 23 and DB 166 by InVO4- TiO2 under visible light for 300 min.