Interface and defect engineering of hierarchical Ti3C2/Co@CeO2-NCNT nanocomposite for ultrasensitive electrochemical determination of pesticide bithionol

Rational regulation of the interface and realization of synergistic electrocatalytic activity in functionalized structure represent a key strategy for developing high-selectivity electrochemical sensors toward emerging environmental pollutants. In this work, a hierarchical Ti 3 C 2 /Co@CeO 2 -NCNT composite electrode was rationally designed and fabricated via defect and interface engineering, and employed innovatively as a high-performance sensing platform for trace-level detection of bithionol (BT) in aquatic environments. In this architecture, the 2D conductive Ti 3 C 2 framework effectively disperses and stabilizes Co@CeO 2 -NCNT components, providing abundant pathways for efficient electron transfer. The as-obtained sensor delivers outstanding analytical performance, including a low limit of detection 2.82 nM, a wide linear range of 5 nM to 9 μM, and excellent stability and practicality in real water samples with satisfactory recoveries of 97.3% - 104.4%. Density functional theory (DFT) calculations confirm that p-d-f orbital hybridization greatly enhances BT adsorption, interfacial charge-transfer kinetics, and overall catalytic efficiency. This work not only provides a novel and sensitive electrochemical platform for BT detection, but also offers valuable guidance for the targeted design of advanced electrocatalytic materials for specific environmental pollutants by clarifying the synergistic mechanism of interface engineering and defect modulation.