High Sensitivity and Selectivity of PEDOT/Carbon Sphere Composites for Pb²⁺ Detection

Heavy metal ions impair human health and irreversibly damage the ecosystem. As a result, it is critical to create an efficient approach for identifying heavy metal ions. The electrochemical sensor method is a type of detection method that is highly sensitive, low in cost, and allows for real-time monitoring. In this study, solid carbon spheres were made using resorcinol and formaldehyde as raw materials, followed by the formation of PEDOT/carbon sphere composites via in situ oxidative polymerization, and Pb²⁺ was detected utilizing them as electrode modification materials. The structure of the PEDOT/carbon spherical composites was analyzed using scanning electron microscopy (SEM), X-ray diffraction (XRD), and Fourier transform infrared spectroscopy (FTIR). To investigate the electrochemical properties of these composites, electrochemical impedance spectroscopy (EIS), cyclic voltammetry (CV), and differential pulse voltammetry (DPV) were employed. In addition, the detection mechanism of the material for Pb²⁺ was studied using CV. The PEDOT/carbon sphere sensor showcased an extensive linear detection range of 7.5 × 10^-2 to 1.0 μM for Pb²⁺ ions, achieving a low limit of detection (LOD) of 3.5 × 10^-2 nM and displaying exceptional selectivity. These results can be attributed to its large surface area, superior electrical conductivity, and outstanding electron transport properties. This study offers an effective material for detecting low concentrations of Pb²⁺, with potential applications in future Pb²⁺ detection.