Carbendazim (CBZ) is widely used for crop protection and its residues threaten human health and the environment. Therefore, developing an effective electrocatalyst is important for the extremely sensitive detection of CBZ. Lattice-strain engineering is an effective strategy to change its electronic structure and ultimately optimize the catalytic performance of materials, which can be used as a modification method to improve the detection performance of electrochemical sensors. Herein, a NiFeLDH@HsGY-NH2/MWCNTs heterojunction with strain effect is prepared by the electrostatic self-assembly method. The structure, morphology, composition, crystallinity and electrochemical performance of NiFeLDH@HsGY-NH2/MWCNTs are analyzed using various instrumental techniques, in which geometric phase analysis (GPA) and X-ray diffraction (XRD) images confirm the lattice-strain generated in NiFeLDH@HsGY-NH2/MWCNTs. The results indicate that the prepared electrochemical sensor exhibited an excellent response for carbendazim (CBZ) in the linear range of 0.05–50.00 μM with a detection limit of 10.00 nM (S/N = 3) under the optimal detection conditions. By analyzing the reasons for the improvement of the catalytic performance of the composite material, it is found that the composite of MWCNTs not only improves the conductivity of NiFeLDH but also regulates the electronic structure of metal atoms through double effects. This study provides new insights into the design of efficient and low-cost catalysts to facilitate electrochemical sensor applications.
Reduced holey graphene (rHG) has a large number of nanopores and a 3D porous network. As the pore size of the in-plane hole becomes larger, the defect density and the number of edges of rHG increase, which is conducive to accelerating electron transfer and exhibiting excellent electrochemical performance. The electrochemical sensor based on rHG successfully detects carbendazim in the concentration range of 0.1−100 μM with low detection limit (13.14 nM) and the sensitivity reaching to 22.541 μA μM −1 cm −2 . Furthermore, the sensor exhibits outstanding anti-interference, stability, and satisfactory recoveries in real samples.
Graphene nanosheets (GS) with approximately 10–15 layers was prepared via ultrasonic exfoliation of graphite powder in N -methyl-2-pyrrolidone (NMP), and confirmed using transmission electron microscopy (TEM) and atomic force microscopy (AFM). X–ray photoelectron spectra (XPS) and Raman spectra were employed to get further insights into the structural characteristics of exfoliated GS. On the surface of the GS modified glassy carbon electrode (GS/GCE), oxidation signals corresponding to carbendazim, a widely used pesticide, were greatly improved due to the higher accumulation ability, as determined by chronocoulometry. The oxidation mechanism of carbendazim was studied using a rotating disk electrode, and two electrons were transferred. Depending on the signal amplification of GS, a highly sensitive analytical platform for carbendazim was constructed. The linear range was from 1.0 to 300.0 μg L −1 (0.005–1.57 μM), and the detection limit was 0.15 μg L −1 (0.78 nM). Finally, this newly developed sensor was used to detect carbendazim in ground water, soil, and cucumber samples with satisfactory accuracy.
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