Two-Dimensional (2D) Layered Metal–Organic Framework (MOF) Composites as an Electrochemical Sensor for Nitrofurans

A two dimensional layer iron metal–organic framework (MOF), [Fe (bipy)(C 4 O 4 )(H 2 O) 2 ]×3H 2 O (where bipy = 4,4’-bipyridine、 C 4 O 4 2- (squarate) = dianion of squric acid) has been successfully synthesized. Hydrothermal synthesis was employed to incorporate these Fe-MOFs into reduced graphene oxide (rGO) nanosheets, forming Fe-MOF/rGO composites. SEM, TEM, XRD, XPS, and contact angle measurements were employed to analyze the composites. TEM studies revealed that the rod-shaped Fe-MOFs were uniformly dispersed on the rGO sheets. Incorporating Fe-MOF into rGO resulted in enhanced performance, which can be attributed to the composites' large surface area, chemical stability, and high electrical conductivity. The Fe-MOF/rGO modified electrodes exhibited significantly improved response signals for the electrochemical sensing of nitrofurazone, showcasing a lower detection limit. The sensor also demonstrated reproducible and stable anti-interference properties. To elucidate the mechanism behind the enhanced sensing performance, grand canonical Monte Carlo (GCMC) calculations were conducted. These calculations indicated that the interface between Fe-MOF and rGO effectively absorbed an increased number of NFZ molecules. These findings underscore the substantial improvement in the electrochemical performance of Fe-MOF/rGO composites, positioning them as promising materials for practical applications in nitrofurazone sensing.