Self-assembled multilayer Nb2C MXene/MnFe2O4 electrochemical sensor with Schottky junctions for the detection of acetaminophen and dopamine

The electrochemical sensors with the ability of biomolecule detection can be used for human life and health monitoring. In this work, we developed an electrochemical sensor with a Schottky junction by electrostatic interaction, composed of Nb2C MXene and MnFe2O4. Large reactive groups (O, OH, Cl, or F) are observed at the ends of the Nb2C MXene surface. Meanwhile, there are abundant oxygen vacancies and surfaces of MnFe2O4 which bring it favorable heterogeneous catalytic properties. Among them, the chemical self-assembly of MnFe2O4 nanoparticles on Nb2C MXene enhances the binding strength of the material through electrostatic interaction, promotes charge transfer across the interface, and modulates the electronic and nanostructural characteristics of the N-MFO (MnFe2O4/Nb2C MXene). The results demonstrate that the sensing performance of N-MFO4 for Acetaminophen (AP) and Dopamine (DA) is significantly improved compared to Nb2C MXene and MnFe2O4 modified electrodes, respectively. The obtained limits of detection (LOD) of N-MFO4 modified electrode for AP and DA being 0.079 and 0.070 μM, respectively. The combination of electrodes modified with highly active nanomaterials is supposed to build a portable electrochemical analysis system with high sensitivity, good selectivity, favorable stability, simple operation and low cost, and promote the application of electrochemical sensors in related fields.