Photocatalytic degradation of Congo Red dye by using nano ZnO and Ni-Co-ZnO nanocomposites

Photocatalysis has attracted significant attention as a potential issue for the degradation of toxic organic pollutants such as Congo Red. In this research spherical Pure ZnO nano particles and Ni-Co-ZnO nano composites (Zn0.95Ni0.04Co0.01O,  Zn0.95Ni0.025Co0.025O and  Zn0.95Ni0.01Co0.04O) have been synthesized by precipitation method. X- ray diffraction, Fourier transform Infra Red ,field emission scanning electron microscopy, EDX  and ICP analysis confirmed the structure and composition of the samples. The x-ray diffraction analysis (XRD) showed that all samples prepared were about Wurtzite structure and average crystal size of 17nm. Field emission scanning electron microscopy (FESEM) analysis revealed the spherical shape of all samples. The Fourier transform infrared spectroscopy (FT-IR) revealed bands at 435 cm-1, 480 cm-1 and  525 cm-1 are related to Zn-O bonds, related to the stretching vibrating bonds of ZnO. The results illustrated the Ni and Co ions substituted the Zn ions in ZnO crystal lattice successfully. The results showed that some of doped Ni-Co ZnO exhibit enhanced photocatalytic activity , as compared to pure ZnO. Kinetic of de-colorization process for all photo-catalysts followed psedu first order. In degradation process The best photocatlyst was (Zn0.95Ni0.04Co0.01O).