CdO/ZnO nanohybrids: facile synthesis and morphologically enhanced photocatalytic performance

A series of CdO/ZnO nanohybrids of different compositions were synthesized by a wet chemical method and investigated in detail. The nanohybrids were characterized by various techniques such as wide angle X-ray diffraction (XRD), diffuse reflectance UV-vis spectroscopy, transmission electron microscopy (TEM), and field emission scanning electron microscopy (FE-SEM). The results revealed that the crystal structure and optical properties of the nanohybrids were almost the same for all the compositions. FE-SEM images showed that the morphology of CdO/ZnO was hexagonal like microspheres, and the 0.75 : 1 Cd/Zn sample had a well-proportioned morphology. Three different dyes viz crystal violet, congo red and rhodamineB were used for the photocatalytic studies in a photoreactor and monitored with a UV-visible spectrometer. The nanohybrids showed excellent photocatalytic degradation compared to pure CdO and ZnO. In particular, nanohybrids with 0.75 : 1 (Cd : Zn) composition ratio exhibited better results compared to all other CdO/ZnO nanohybrids, which may be attributed to the improved charge separation at the heterojunction interface. Electron-hole recombination at hetero junction of CdO/ZnO nanohybrids.