Green Synthesis: Characterization, and Antibacterial Evaluation of Cobalt Oxide Nanoparticles using Syzygium Aromaticum Leaf Extract

Abstract

Green synthesis has emerged as a sustainable alternative to conventional physical and chemical routes for the preparation of metal oxide nanoparticles, offering advantages such as environmental compatibility and reduced use of hazardous reagents. In the present study, cobalt oxide nanoparticles were synthesized using an aqueous leaf extract of Syzygium aromaticum, where plant-derived phytochemicals served as reducing and stabilizing agents. The structural, morphological, elemental, and optical properties of the synthesized nanoparticles were systematically investigated using X-ray diffraction (XRD), scanning electron microscopy with energy-dispersive X-ray spectroscopy (SEM-EDX), Fourier transform infrared spectroscopy (FTIR), and UV-visible spectroscopy. XRD analysis confirmed the formation of crystalline cobalt oxide, while SEM micrographs revealed agglomerated cobalt oxide nanostructures. Elemental composition analysis verified the presence of cobalt and oxygen, and FTIR spectra indicated the involvement of functional groups associated with the plant extract in nanoparticle formation. The optical absorption characteristics were examined using UV-visible spectroscopy. Furthermore, the antibacterial activity of the synthesized cobalt oxide nanoparticles was evaluated using zone-of-inhibition assays with appropriate controls, demonstrating their potential antimicrobial effectiveness. The results suggest that Syzygium aromaticum-mediated green synthesis provides a viable and eco-friendly route for producing cobalt oxide nanoparticles with functional properties suitable for biological applications.