Biosynthesis and Characterization of Copper Oxide Nanoparticles †

Abstract

In this paper, we report the use of the natural extract of Echinacea leaves [Echinacea purples] for the biosynthesis of copper oxide nanoparticles, with copper nitrate [Cu(NO3)2 3H2O] used as a metal precursor salt. The synthesized CuO was investigated using Fourier transform infrared spectrometry (FTIR), Raman spectroscopy, X-ray diffraction, scanning electron microscopy (FESEM), and energy dispersive X-ray analysis (EDX). The FTIR spectra confirm not only the presence of the Cu-O bond by the appearance of the characteristic peak at 402 cm−1, but also the presence of the functional groups characteristic of the biomolecules present in the plant extracts used. The Raman spectra indicate peaks at wavelengths of 272 and 610 cm−1, which are characteristic bands for CuO. The XRD diffractogram indicates the formation of a monoclinic crystalline structure by the appearance of distinctive peaks corresponding to (110), (002), and (111) planes, with an average crystallite size of 15 nm. The SEM images reveal the formation of spherical particles with dimensions below 40 nm. The EDX spectrum confirms the presence of the peaks attributed to (C) and (O) atoms without other impurities. Due to the small size, morphology, and precise elemental composition of CuO NPs, this approach allows the synthesis of biomaterials with applicability in the development of antibacterial agents and biosensors.