The effect of CdO content on the crystal structure, surface morphology, optical properties and photocatalytic efficiency of p-NiO/n-CdO nanocomposite

Pure NiO nanoparticles and NiO-CdO nanocomposite were prepared with different content of CdO by simple chemical precipitation method at 800 degrees C for 3 h. Crystal structure, surface morphology, elemental composition and function groups present in the prepared samples were characterized by XRD, SEM, EDX, Raman and FTIR analysis, respectively. From XRD, preparation of pure NiO and formation of nanocomposite samples confirmed by the presence of characteristic diffraction peaks of cubic phase structure of NiO and CdO. The particle size increases from 26 to 34 nm with the increase of CdO content in the prepared samples. SEM images show the spherical shape of NiO and plate like shape of nanocomposite samples. The EDX analysis revealed that the absence of any impurity peaks indicates the high quality of prepared samples. Raman and FTIR spectra show the fundamental peaks of NiO and CdO in the samples. The best photodegradation efficiency of methyl orange dye i.e. 60% was achieved as a result of the decrease in the energy band gap from 3.42 to 2.92 eV at the optimum content of CdO (0.12 wt%).