Nitrogen-defect-driven rGO tailored terbium vanadate nanorices as an electrochemical platform for carbendazim...

The prompt and accurate identification of carbamate fungicides in food has emerged as a crucial concern. Here, we developed zircon-type terbium vanadate intertwined nitrogen-doped reduced graphene oxide (TbVO₄@N-rGO) nanocomposite through ultrasonication for electrochemical detection of carbendazim. Comprehensive structural and surface analyses validate the formation of pure, crystalline TbVO₄ phase with a unique nanorice morphology. The superior sensing performance arises from N-doped rGO, which enhanced conductivity and promotes CBZ adsorption through π-π stacking interactions combined with catalytic active sites of TbVO₄ nanorices and defect-driven charge transfer. The modified electrode exhibits a low limit of detection of 1.44 nM, linear range 0.01-1793 μM and high sensitivity of 1.605 μA/μM cm²). Furthermore, DFT calculations provide the optimized structure of CBZ, its electrostatic potential, and HOMO-LUMO energy gap providing ionization potential (I = -HOMO) of 6.1 eV and electron affinity (A = -LUMO) of 0.85 eV. The sensor also exhibited excellent selectivity >5-fold over interferents, stability and reproducibility. When applied to real-world food matrix samples, carrot juice with recovery ranges of 97.11-98.94% (R² = 0.9913) and 97.37-100.30% (R² = 0.9901). Thus, TbVO₄@N-rGO serves as an efficient electrocatalyst for the sensitive accurate detection of CBZ, contributing to improved food quality control.