Evaluation of physicochemical characteristics and antimicrobial activities of copper oxide nanoparticles formed by the solution combustion method

In this paper, copper oxide (CuO) nanoparticles (NPs) was prepared by solution combustion technique. We used copper nitrate as an oxidizer and malic acid as a fuel to make three different CuO NPs by using different fuel ratios: low (M1), stoichiometric (M2), and high (M3). The XRD patterns show that the CuO NPs have the monoclinic structure with an average grain size of 17, 20, and 18 nm corresponding to M1, M2, and M3 respectively. The SEM images revealed that the CuO NPs prepared display bush as morphology consisting of a wheat-like structure for M1, rod-like structure for M2, and sheet-like structure for M3 sample. The FTIR spectrum shows that CuO NPs is successfully formed in all of the samples. A bandgap of around 3.26 eV can be seen in the UV-Vis spectrum. Also, the three samples are possessing antibacterial activity and are influenced by the crystalline size, shape, purity, and uniformity of the crystals. Among the three samples with a difference of morphology, the most influencing factor of antibacterial activity being the shape that of other larger-sized particles