Synthesis, characterization, and evaluation of antibacterial and antifungal activities of CuO-ZnO-Co3O4 nanocomposites

The co-precipitation method was used to prepare CuO, ZnO, Co₃O₄ nanoparticles and CuO-ZnO-Co₃O₄ nanocomposite. The structural, morphological, and optical properties of the prepared samples were studied using X-ray diffraction (XRD), total reflection X-ray fluorescence (TXRF), transmission electron microscopy (TEM), selected area electron diffraction (SAED), diffuse reflectance spectroscopy (DRS), and zeta potential. XRD analysis revealed that the crystal structures of CuO, ZnO, and Co₃O₄ nanoparticles are monoclinic, hexagonal, and cubic, with average crystallite sizes of 30.8 nm, 31.8 nm, and 32.8 nm, respectively. For CuO-ZnO-Co₃O₄ nanocomposites, the corresponding sizes were 24.9 nm, 13.6 nm, and 16.1 nm. The optical bandgaps of CuO, ZnO, Co₃O₄ nanoparticles, and CuO-ZnO-Co₃O₄ nanocomposites were 1.5 eV, 3.14 eV, 1.2 eV, and 1.3 eV, respectively. In this study, the antibacterial activity of CuO-ZnO-Co₃O₄ nanocomposite against Gram-negative bacteria (<i>E. coli, Klebsiella, pseudomonas, and Salmonella</i>) and Gram-positive bacteria (<i>Staphylococcus aureus</i>) was investigated and compared with the antibiotic <i>Azithromycin</i>. In addition, the effect of the nanocomposite on fungi was studied and compared with the antifungal <i>Mystatin</i>.