Leaf extract of Cimbopogan citratus supported CuO/ZnO nanocomposite and their applications in photocatalytic and antibacterial activities

Abstract

We have focused on the green synthesis of copper oxide nanoparticles (CuONPs) and zinc oxide nanoparticles (ZnONPs) and CuO coated with ZnO nanocomposite (CuO/ZnO) by using leaf extract of Cimpobogan citrates (CC) as reducing and stabilizing agent. Copper sulfate pentahydrate (CuSO4.5H2O) and zinc acetate dihydrate (Zn(CH3COO)2.2H2O) are the forerunners in the hydrothermal synthesis. The prepared ZnONPs, CuONPs and CuO/ZnO nanocomposite were characterized using various instrument techniques such as Fourier Transform-Infrared spectroscopy (FT-IR), UV-visible spectroscopy (UV-Vis), X-ray diffraction pattern (XRD), Scanning electron microscope (SEM), Energy dispersive X-ray analysis (EDAX) and High Resolution-Transmission Electron microscope (HR-TEM). The results showed that the average size of CuO/ZnO nanocomposite was 20-50 nm. The Tauc plot of CuO/ZnO nanocomposite shows low band gap (1.56ev). Under visible light illumination, methylene blue (MB) was degraded photocatalytically using ZnONPs, CuONPs and CuO/ZnO nanocomposite which was then examined using UV-visible spectroscopy. In comparison to ZnONPs (65%) and CuONPs (80%), CuO/ZnO nanocomposite showed superior photocatalytic activity for the breakdown of MB with a high percentage degradation efficiency (85%). The photocatalytic degradation rate constant was evaluated by using a pseudo-first order kinetic equation. Additionally, the agar disc diffusion method was used to examine the antibacterial activity against two bacterial strains (Escherichia coli and Staphylococcus aureus) and a sizable zone of inhibition against the bacterial strains was found.