Gold electrode modified using MXene (Ti3C2)-CeO2 nanocomposite for electrochemical sensing of Copper (II) ions

Abstract This study presents a novel approach for detecting trace copper (II) ions using a gold electrode surface functionalized with a MXene (Ti 3 C 2 )—cerium oxide (CeO 2 ) nanocomposite. The MXene—cerium oxide nanocomposite along with the cerium oxide nanoparticles, was synthesized through the sonochemical method, with optical characteristics assessed via diffuse reflectance spectroscopy. X-ray diffraction (XRD) and Fourier transform infrared spectroscopy (FTIR) were employed to evaluate the crystal structure and functional groups of the synthesized material, respectively. Among other available techniques, electrochemical methods—particularly cyclic voltammetry (CV)—were selected for the detection of copper (II) ions. The kinetics of interaction between the electrode and analyte were determined to be controlled by adsorption, as indicated by the voltammograms recorded across scan rates of 5 to 300 mV s −1 . Differential pulse voltammetry (DPV) was employed to evaluate the sensor’s detection capabilities over a broad concentration range, from femtomolar (fM) to micromolar (μM) levels. The resulting ultralow limit of detection (LOD) of 0.34 fM surpasses the World Health Organization’s thresholds, making this sensor highly effective for the sensitive detection of copper (II) ions. The repeatability, reproducibility, and stability of the modified sensor were assessed to validate its suitability for real-world applications.