Preparation And Electroanalytical Application Of H₂N-Fe-MIL-88B-Based Electrocatalyst

As a kind of porous crystal material with periodic network structure,metal-organic frameworks?MOFs?have the structural characteristics of inorganic and organic polymer compounds,and have developed into one of the research hotspots in the field of new functional materials.However,the applications of MOFs in the field of electrochemical research are limited due to their weak conductivity and poor electrochemical stability.In recent years,the method of functionalizing MOFs crystals can not only effectively improve the overall conductivity of the composite,but also the synergistic effect of the components in the composites gives the composite some new functions.Therefore,the application of MOFs in the field of electrochemistry has been effectively expanded.In this paper,iron-based metal-organic framework?H₂N-Fe-MIL-88B?is functionalized by different carbon nanomaterials.H₂N-Fe-MIL-88B@OMC and Fe3O4/N/C@MWCNTs composites were successfully prepared.These composites are systematically characterized by a series of methods.In addition,the performances of electrochemical sensors based on two novel composites were also investigated,respectively.The specific works in the paper are as follows:1.One-step hydrothermal method was used to prepare a novel hybrid composite?H2N-Fe-MIL-88B@OMC?of iron-based metal organic framework?H2N-Fe-MIL-88B?and ordered mesoporous carbon?OMC?.Compared with pure H2N-Fe-MIL-88B crystals,the introduction of OMC can shrink the size of H₂N-Fe-MIL-88B,increase the specific surface area,and reduce the electron transfer resistance of H2N-Fe-MIL-88B@OMC.And other H₂N-Fe-MIL-88B@OMC composites with different carbon contents were obtained using the same synthesis procedure.Under the optimal conditions,an electrochemical sensor based on H₂N-Fe-MIL-88B@OMC-3/GCE shows excellent sensing performance for p-nitrotoluene?p-NT?and hydrazine?N2H4?with satisfactory anti-interference ability as well electrochemical stability.It is worth noting that this sensor has an extremely high sensitivity for detecting low concentrations of N2H4.At the same time,H₂N-Fe-MIL-88B@OMC-3/GCE can also be used to detect these two environmental pollutants in actual water samples,which has high practical value.2.The H₂N-Fe-MIL-88B@MWCNTs composite was successfully obtained for the first time by high-temperature calcination of the hybrid of in-situ insertion of multi-walled carbon nanotubes?MWCNTs?into H₂N-Fe-MIL-88B.Compared to a simple mechanical-physical mixture of Fe3O4/N/C and MWCNTs,this nanocomposite has higher conductivity,greater specific surface area and superior stability.In addition,the derivatized composite exhibits excellent catalytic activity for electrocatalytic oxidation of acetaminophen?AP?and reduction of metronidazole?MNZ?due to synergy between the components.