The photocatalytic degradation and mineralization of Reactive Orange 30 on NiO/CuO/TiO2 ternary composites have been studied using solar light irradiation. The NiO/CuO/TiO2 ternary composites were prepared by producing ethanolic dispersions containing varied amounts of NiO and CuO/TiO2 (3wt% to 15wt.%), followed by annealing at 300 °C. SEM, UV- Vis DRS, PL, XRD and FTIR analysis have been used to characterize the unary (parent photocatalysts), binary and ternary composites. Under solar light irradiation, NiO/CuO/TiO2 ternary composites exhibited an excellent photocatalytic activity in degradation of reactive orange 30 in aqueous solution, whereas the NiO/TiO2, CuO/TiO2 and bare photocatalyst such as NiO, CuO, TiO2 showed lower activities. It was deduced that the remarkable visible-light absorption phenomenon and band gap reduction of the NiO/CuO/TiO2 ternary composites taking place. It paves way for the photogenerated electron transfer between CB of the NiO, CuO, TiO2 semiconductors and also holes shifting between VB of above mentioned materials. The NiO/CuO/TiO2 ternary composite shows good photostability and the photocatalyst retains 94% of its initial activity in the seventh cycle, respectively.

The photocatalytic degradation efficiency of CoTiO3 coupled Sr, N codoped TiO2 has been examined by the degradation of Reactive Yellow 84 (RY 84) under solar light irradiation. The efficient CoTiO3/Sr, N codoped TiO2 based heterojunction composite was prepared via dispersed method and the results were compared with Sr, N codoped TiO2 and bare TiO2. The prepared photocatalysts were analyzed by x-ray diffraction [XRD], scanning electron microscopy [SEM] and diffused reflectance spectroscopy [UV-DRS] and Photoluminescence study [PL] , which implies the crystal structure, surface morphology, optical properties and quenching of electron role recombination. The charge separation of CoTiO3/Sr, N codoped TiO2 heterojunction composite has been improved as a result of coupling CoTiO3 and Sr, N codoped TiO2 with different energy levels and the responsible for the enhancement in the rate of photocatalytic degradation. The CoTiO3/Sr, N codoped TiO2 heterojunction composite shows better photostability at continuous photocatalytic runs. Our report will helps in the establishment and development of photocatalytic research.