Green synthesis, characterization, and evaluation of antimicrobial and antioxidant activities of CuO, Co3O4, and CuO-Co3O4 Nano system using Moringa stenopetala plant leaf extracts

Objective(s): The purpose of this study was to synthesize copper oxide nanoparticles (CuO NPs), cobalt oxide nanoparticles (Co3O4 NPs), and CuO-Co3O4 nano system using Moringa stenopetala plant leaf extract. These nanoparticles were specifically developed for their antioxidant and antibacterial properties. Materials and Methods: The nanoparticles were synthesized by a green synthesis approach using M. stenopetala leaf extract. Comprehensive characterization using spectroscopic techniques such as X-ray diffraction (XRD), UV-visible spectroscopy, scanning electron microscopy (SEM), Fourier transform infrared (FT-IR), and thermogravimetric analysis (TGA) was executed. Results: UV-Vis analysis revealed an energy bandgap of 3.32 eV for CuO NPs, 3.36 eV for Co3O4 NPs, and 3.66 eV for CuO-Co3O4 nano system. XRD analysis revealed that CuO NPs have a monoclinic crystal structure with an average crystallite size of 11.59 nm, whereas Co3O4 NPs have a cubic crystal structure with an average crystallite size of 12.25 nm. The CuO-Co3O4 nano system exhibited an average crystal size of 9.53 nm. The SEM images showed inhomogeneous composition and large granular particles of CuO NPs, inhomogeneous cubic shape and size with encapsulation and hydrogen bonding aggregation of Co3O4 NPs, and particle heterogeneity. The CuO-Co3O4 nano system. FT-IR analysis confirmed the presence of bioactive molecules such as flavonoids, tannins, terpenoids, steroids, glycosides, saponins, and phenols that actively participate in the synthesis process. Conclusion: The synthesized CuO-Co3O4 nano system showed superior inhibitory effects against the selected bacterial strains compared to CuO NPs and Co3O4 NPs. Furthermore, they showed excellent antioxidant activity. These results highlight the significant potential of CuO-Co3O4 nano system for a wide range of applications due to their remarkable bacterial inhibition and radical scavenging properties.