Eco-friendly Ocimum tenuiflorum green route synthesis of CuO nanoparticles: Characterizations on photocatalytic and antibacterial activities

Abstract

Today, in the 21st century, metal oxide nanoparticles by employing green technologies are being investigated for their potential applications in the field of catalysts, drugs, sensors, optics, cosmetics, and semiconductors. In this perspective, herein, an efficient and sustainable Ocimum tenuiflorum green route has been utilized to synthesize and evaluate the photocatalytic and antibacterial activities of CuO nanoparticles. The samples of CuO nanoparticles were synthesized by using various concentrations of Cu(CH3COO)2·H2O (5, 10, and 50 mmol kg−1) at 70 °C and pH 11.5. The so-synthesized CuO nanoparticles were first characterized by recording the UV–visible spectra in the range 360–368 nm. The X-ray diffraction (XRD) study reveals that the crystallite size of the so-obtained nanoparticles is lying between 8.42 and 9.24 nm. Analysis of the samples by scanning electron microscopy (SEM) and transmission electron microscopy (TEM) indicated the agglomeration of elliptical/spherical/rice shaped particles with size in the range 6–18 nm. The elemental analysis from energy dispersive X-ray spectroscopy (EDS) further confirmed the formation of pure CuO nanoparticles. The results of antibacterial experiments have shown that so-synthesized CuO nanoparticles are good inhibitors for the growth of pathogens, Bacillus subtilis, Staphylococcus aureus, and Escherichia coli. Further, investigations on photocatalytic activity suggest that CuO nanoparticles can be employed as photocatalyst in the degradation process of methyl orange (MO) dye. Up to 96.4 ± 0.83% degradation of MO has been obtained in just 24 min. The photocatalytic degradation reaction is following the pseudo-first-order reaction kinetics.