Green synthesis of CuO-NiO nanocomposite using <i>Citrus sinensis</i> peel extract and their significant antibacterial properties against a series of pathogenic strains

The present work delineates the environmentally friendly synthesis of a CuO-NiO nanocomposite employing an extract derived from the peel of Citrus sinensis as both a capping and reducing agent. The green-synthesized nanocomposite was characterized using X-ray Diffraction (XRD), Scanning Electron Microscopy (SEM), and Diffuse Reflectance Spectroscopy (DRS). XRD for crystallinity, SEM for surface morphology, and DRS for bandgap determination were used to characterize the synthesized nanocomposite. The average crystalline size of the nanocomposite is 24.75 nm. SEM revealed that CuO-NiO nanocomposites have a rod-like surface morphology. The bandgap of the green-synthesized nanocomposite is determined to be 2.75 eV from reflectance data. Using the agar well diffusion technique, the antibacterial activity of the study was evaluated against three Gram-positive and four Gram-negative bacterial strains. The findings in the present work demonstrate that the CuO-NiO nanocomposite exhibits nearly uniform antibacterial activity (ABA) against all tested Gram-negative bacterial strains, suggesting its potential applicability for various medical uses.