Eco-Friendly Phytochemical-Derived Co₃O₄@Ag Nanoparticles for Ethanol Oxidation and Antibacterial Activity

Abstract

A sustainable synthesis method was employed to produce Co3O4 and Co3O4@Ag nanoparticles for ethanol electro-oxidation and antibacterial applications. The eco-friendly approach involved utilising leaf extracts from hibiscus sabdariffa for nanoparticle synthesis. Various characterisation techniques, such as UV-Visible spectroscopy, X-ray diffraction, Fourier transform infrared spectroscopy, scanning electron microscopy, and dispersive X-ray analysis were employed to analyse the properties of the nanoparticles synthesised via green method. FTIR analysis indicated that biomolecules present in the leaf extracts contributed to reducing the metallic salts during synthesis. The average particle size of the nanoparticles was determined using Scherrer's equation, which considered the width of the diffraction peaks in the XRD data. SEM analysis confirmed the morphology and well-dispersed nature of the Co3O4 and Co3O4@Ag nanoparticles at nanoscale level. Incorporating Ag nanoparticles into Co3O4 facilitated ethanol adsorption, leading to enhanced electro-oxidation by reducing energy barriers and resulting in significant electro-oxidation activity. Moreover, the antibacterial efficacy of both Co3O4 and Co3O4@Ag nanoparticles was evaluated against Gram-positive and Gram-negative bacteria.