CuO nanoparticles: preparation, characterization, optical properties, and antibacterial activities

Firstly, new copper precursor was prepared from the mixture of Cu(CH₃COO)₂∙H₂O and salicylic acid (1:1 weight ratio) ground for 5 min, and secondly, copper oxide nanoparticles were prepared by calcination of copper precursor at 500 ºC and 600 ºC for 1.5 h. The products were characterized by Fourier Transform infrared (FT-IR), UV–Vis and photoluminescent (PL) spectroscopy, X-ray powder diffraction (XRD), and transmission electron microscopy (TEM). The FT-IR, UV–Vis, PL, and XRD analysis confirmed the formation of CuO nanoparticles of high purity with a monoclinic structure. TEM images showed that the nanoparticles in both samples had almost similar shape with high agglomeration. The optical band gap value was estimated to be 4.5 and 4.8 eV, respectively, for the as-prepared CuO at 500 and 600 ºC, using Tauc’s plot. In addition, antibacterial activity against two gram-positive and two gram-negative stains were studied and the inhibition effect of the as-prepared CuO at 500 and 600 ºC on gram-negative bacteria is higher than that on gram-positive bacteria