Biosynthesized ZnO/Co ₃ O ₄ Nanocomposite-Modified Electrode for Electrocatalytic Lead Detection and Quantification

High Resolution Image Download MS PowerPoint Slide This study employed square wave stripping voltammetry to detect Pb 2+ using a modified electrode made from a watermelon peel extract-assisted ZnO/Co 3 O 4 nanocomposite. The as-prepared nanomaterials’ physicochemical and electrochemical characterizations were elucidated using thermogravimetric analysis and differential thermal analysis (TGA/DTA), X-ray diffraction, ultraviolet–visible diffuse reflectance spectroscopy (UV–vis DRS), scanning electron microscopy–energy-dispersive X-ray spectroscopy, Fourier transform infrared spectroscopy, transmission electron microscopy (TEM), high-resolution transmission electron microscopy, selected area electron diffraction, Brunauer–Emmett–Teller (BET), X-ray photoelectron spectroscopy, cyclic voltammetry, and electrochemical impedance spectroscopy techniques. The electrochemical sensing capability of ZnO nanoparticles (NPs) was enhanced by creating a ZnO/Co 3 O 4 nanocomposite, which improved the conductivity of the ZnO NPs through the incorporation of Co 3 O 4 . The peel extract aided in creating a ZnO/Co 3 O 4 nanocomposite-modified electrode that offers more active sites for the detection and quantification of Pb 2+ . Before the detection and quantification of Pb 2+, experimental variables, such as the deposition potential and deposition time, were optimized. The suggested limit of detection and limit of quantification were determined to be 0.03923 μmol/L and 0.131 μmol/L, respectively, in the concentration range of 0.371–0.405 μmol/L. The prepared nanosensor demonstrated sensitivity and simplicity, making it suitable for various environmental analyses.