INVESTIGATION OF THE STRUCTURAL AND OPTICAL PROPERTIES OF COBALT DOPED COPPER OXIDE/ZINC OXIDE NANOCOMPOSITES FOR TREATMENT OF METHYL BLUE DYE-CONTAMINATED WASTE WATER

Abstract

Transition metal oxide nanocomposites are attracting significant research interest due to their potential applications in optoelectronic devices, solar cells, photocatalysis, and antibacterial materials. This study focuses on CuO-Zn1-xCoₓO (x = 0.0, 0.02, 0.04, 0.055, and 0.07) metal oxide nanocomposites synthesized by the sol-gel combustion method. The synthesized nanocomposites were characterized using X-ray diffraction (XRD), Fourier transform infrared (FTIR) spectroscopy, Brunauer-Emmett-Teller (BET) analysis, ultraviolet-visible (UV-vis) spectroscopy, and photoluminescence (PL) spectroscopy. XRD confirmed the formation of monoclinic crystal structure of CuO and hexagonal crystal structure of ZnO in all nanocomposite compounds. An average crystal size obtained from XRD parameters was ranging from 26.8 to 31.8 nm, confirming the formations of nanostructured since the values are in the range of nano scale. Moreover, FTIR analysis verified the presence of functional groups consistent with the composite structure. BET measurements revealed high surface areas (48.86 to 51.07 m²/g) for all samples. UV-vis spectroscopy indicated prominent absorption in the UV and visible regions, with Co ions doped nanocomposites exhibiting enhanced absorption compared to pristine CuO-ZnO composite. The band gap energy, calculated from UV-vis data, decreased from 3.27 eV to 2.88 eV with increasing Co doping. The PL analysis confirmed a reduction in electron-hole recombination when Co ions doped into CuO-ZnO nanocomposite, Photocatalytic activity tests revealed enhanced performance against methylene blue dye under UV light irradiation for Co ions doped nanocomposites. Among the samples, CuO-Zn₀.₉₄₅Co₀.₀₅₅O exhibited the highest photocatalytic activity.