Normal spinel CoCr2O4 and CoCr2O4/TiO2 nanocomposite as novel photocatalysts, for degradation of dyes

For the first time, CoCr₂O₄/TiO₂ nanocomposite as a novel photocatalyst with different TiO₂ contents have been prepared by the sol-gel method. The techniques of X-ray diffraction (XRD), scanning electron microscopy and transmission electron microscopy (TEM) have been employed to characterise the synthesised nanocatalysts. The XRD and TEM results indicated that CoCr₂O₄ has a cubic normal spinel structure and the particle size of CoCr₂O₄ is about 30 nm. As the first report, degradation of methylene blue and methyl orange is performed by CoCr₂O₄ and CoCr₂O₄/TiO₂ nanocomposite under ultraviolet irradiation. The results showed that the rate of degradation of dyes with CoCr₂O₄/TiO₂ is much higher compared with that of CoCr₂O₄ and TiO₂. The photocatalytic activities were carried out under varying parameters such as irradiation time, the pH of the solution, the catalyst amount and substrate concentration.