V₄C₃T_x MXene-modified glassy carbon electrode for the electrochemical detection of cadmium, lead and copper ions

Water pollution induced by heavy metal ions is growing increasingly severe and endangers human health significantly. Here, a high-performance electrochemical sensor for Cd²⁺, Pb²⁺ and Cu²⁺ detection in aqueous samples was fabricated by modifying V₄C₃T_x MXene on a glass carbon electrode (GCE). V₄C₃T_x was prepared through selective etching, and its structure and chemical compositions were characterized using scanning electron microscopy (SEM), X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS) and Raman spectroscopy. The results demonstrated that the distinctive two-dimensional lamellar architecture and multivalent vanadium of V₄C₃T_x MXene provided an ideal platform for efficient heavy metal ion enrichment and electrochemical response. The limit of detection (LOD) was 19.4 nM for Cd²⁺, 9.7 nM for Pb²⁺, and 29.1 nM for Cu²⁺. Besides, the V₄C₃T_x/GCE was utilized to detect Cd²⁺ and Pb²⁺ simultaneously, with the LODs to be 24.1 and 12.2 nM. Similarly, the V₄C₃T_x/GCE was applied for the detection of Pb²⁺ and Cu²⁺ simultaneously, and the LODs were 12.6 and 34.5 nM, respectively. The V₄C₃T_x/GCE exhibits excellent repeatability, reproducibility, anti-interference performance and stability, and demonstrates successful application to the analysis of actual water samples.