Synergistic Ti 3 C 2 T x MXene–VS 2 nanocomposite electrode for ultrasensitive electrochemical detection of lead ions

Abstract The persistent toxicity and bioaccumulation of lead ions (Pb 2+ ) in aquatic systems pose significant risks to environmental and public health, necessitating the development of reliable trace-level detection strategies. In this work, a high-performance electrochemical sensor is fabricated through the rational design of a two-dimensional nanocomposite comprising hydrofluoric acid-etched Ti 3 C 2 T x MXene and vanadium disulfide (VS 2 ). The integration leverages the high electrical conductivity and surface functionalization capacity of Ti 3 C 2 T x with the intrinsic redox activity and layered structure of VS 2 , resulting in a composition with accelerated electron transfer rates and improved surface adsorption for Pb 2+ ions. The Ti 3 C 2 T x @VS 2 composite, functionalized on a glassy carbon electrode via a simple drop-casting approach, exhibits a broad linear detection window spanning 1 µ g l −1 to 100 mg l −1 (1 ppb to 100 ppm) and an ultralow detection limit of 0.13 µ g l −1 (ppb), enabling precise monitoring much below regulatory thresholds. The sensor demonstrates excellent repeatability (RSD < 1.02%), high selectivity against common interfering ions. This study highlights the functional synergy of Ti 3 C 2 T x @VS 2 interfaces and establishes a promising route for scalable, high-fidelity electrochemical sensing of heavy metal pollutants in complex environmental matrices.