| Electrochemical sensors are widely used in biomedicine,environmental monitoring,molecular imaging and harmful gas sensing due to their simple preparation,good selectivity and high stability.Metal-organic frameworks are widely used in catalysis,sensing and gas storage due to their unique pore structure.However,due to the poor electrical conductivity and weak electron transport capacity,its further application in the field of electrochemistry is limited.Therefore,it is of great significance to design composite materials to fabricate electrochemical sensors with different functions based on metal-organic frameworks.In this paper,multifunctional composites were prepared by in-situ growth and pyrolysis with metal-organic frameworks as substrate components.The surface morphology and elemental composition of the composites were characterized by scanning electron microscope?SEM?,fourier transform infrared?FT-IR?and X-ray photoelectron spectroscopy?XPS?.The electrocatalytic properties of the composites were studied by cyclic voltammetry?CV?,electrochemical impedance?EIS?and amperometric curve?I-T?.Furthermore,the application of composite modified electrodes in the detection of biological small molecules was further explored.1.In-situ synthesis was used to combine Ni-MOF-74 with graphene oxide.Then,PtNPs was deposited on Ni-MOF-74-GO material by solvent reduction method,and the composite Ni-MOF-74-GO@PtNPs was constructed.By combining GO,PtNPs with Ni-MOF-74,the electrical conductivity of the composites can be improved effectively.The composite material was modified on the surface of glassy carbon electrode by drop coating method.The electrode has good catalytic oxidation ability to uric acid.The electrochemical experiments show that the sensor based on the modified electrode has a wide linear range 1×10-7–2.36×10-4 M,low detection limit2.78×10-6 M?S/N=3?,high response speed and good anti-interference for the detection of uric acid.The sensor has potential application in actual sample detection.2.The derivative NiFe2O4 of metal-organic frameworks NiFe-MOF was prepared by pyrolysis of NiFe-MOF in N2 environment at high temperature.Nanoscale NiCo-LDH was grown in situ on the surface of NiFe2O4 by hydrothermal method.Under low temperature hydrothermal conditions,graphene oxide was covered on the surface of NiFe2O4-NiCo-LDH to form NiFe2O4-NiCo-LDH@GO composite with high conductivity.The composite material was modified on the surface of glassy carbon electrode by drop coating method.The electrochemical sensor based on the modified electrode has a wide linear range 3.5×10-5–4.525×10-3 M,low detection limit 12.94×10-6 M?S/N=3?,good anti-interference for the detection of glucose.The sensor has potential application in the detection of glucose in human serum. |
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