Synergistic Ti ₃ C ₂ T <i> _x </i> MXene–VS ₂ nanocomposite electrode for ultrasensitive electrochemical detection of lead ions

The persistent toxicity and bioaccumulation of lead ions (Pb²⁺) 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 Ti₃C₂T<i>_x</i>MXene and vanadium disulfide (VS₂). The integration leverages the high electrical conductivity and surface functionalization capacity of Ti₃C₂T<i>_x</i>with the intrinsic redox activity and layered structure of VS₂, resulting in a composition with accelerated electron transfer rates and improved surface adsorption for Pb²⁺ions. The Ti₃C₂T<i>_x</i>@VS₂composite, functionalized on a glassy carbon electrode via a simple drop-casting approach, exhibits a broad linear detection window spanning 1<i>µ</i>g l^-1to 100 mg l^-1(1 ppb to 100 ppm) and an ultralow detection limit of 0.13<i>µ</i>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 Ti₃C₂T<i>_x</i>@VS₂interfaces and establishes a promising route for scalable, high-fidelity electrochemical sensing of heavy metal pollutants in complex environmental matrices.