MOF Etching-Induced NiCo-Embedded Hollow N-Doped Carbon Nanocube for Enhanced Ratiometric Molecularly Imprinted Electrochemical Sensing of Carbendazim

Metal–organic framework (MOF)-derived carbon materials are commonly used as sensing materials, but their limited accessibility to active sites and specific surface area restrict their applications. In this study, we proposed a simple method involving facile tannic acid etching and calcination to create NiCo-embedded hollow N-doped carbon nanocubes (NiCo@HNC) using MOFs as sacrificial templates. The resulting NiCo@HNC material has a large specific surface area, improved mass transport channels, and enhanced exposure of electroactive sites due to its unique hollow structure and high porosity, leading to enhanced electrocatalytic activity. Moreover, with the utilization of NiCo@HNC as a substrate material and dopamine as a functional monomer, a ratiometric molecularly imprinted electrochemical sensor was developed for the selective and sensitive detection of carbendazim (CBZ). This sensor demonstrated a wide linear range of 0.0003–10 μM and a low detection limit of 0.1 nM. In addition, the sensor was utilized for the accurate quantification of CBZ in actual carrot/strawberry samples with a recovery range of 96.0–103.0%, indicating its potential for practical application.