Green Synthesis of CuO-ZnO Nanocomposite using Citrus Sinensis Fruit Peel Extract for Electrochemical Detection of Hydrogen Peroxide

In this work, CuO nanoparticles (NPs), ZnO NPs, and CuO-ZnO nanocomposites (NCs) were synthesized using Citrus sinensis fruit peel extract. Then, carbon paste electrodes modified with each nanomaterial (CuO-CPE, ZnO-CPE, and CuO-ZnO-CPE) was fabricated for the electrochemical detection of hydrogen peroxide (H2O2). The prepared metal oxide nanomaterials were characterized using Ultraviolet-Visible (UV-Vis) spectroscopy, Fourier transform infrared (FT-IR) spectroscopy, X-ray diffraction (XRD), and scanning electron microscopy (SEM). The average crystallite sizes for nanomaterials composed of CuO and ZnO NPs and CuO-ZnO NCs were 32.2 nm, 31.7 nm, and 35.38 nm, respectively. A carbon paste electrode modified with CuO-ZnO NCs (CuO-ZnO-CPE) was used to detect H2O2. At CuO-ZnO-CPE, a cathodic peak for H2O2 was seen at about 0.0 V. Under optimum experimental conditions, the developed electrode showed a wide linear range from 0.5 μM to 200.0 μM with a limit of detection (LOD) of about 0.32 μM. The synthesized electrode also showed increased stability, adequate selectivity, and repeatability.