Preparation And Electrochemical Sensing Application Of MOFs Pyrolytic Derivatives

Electrochemical sensors have become the most rapidly developing chemical sensors due to their advantages of high efficiency,high sensitivity,and low cost.In an electrochemical sensor,the redox reaction of the target analyte generates an electrochemical response signal proportional to its concentration.Electrochemical sensors have been widely used in neurotransmitter detection,environmental pollutant analysis and biomedical diagnosis.At the same time,the vigorous development of materials science has also played a positive impact on the development of electrochemical sensing.The electrode material with excellent performance can effectively improve the performance of the sensor.Metal-organic frameworks（MOFs）,also known as porous coordination polymers（PCPs）are composed of metal nodes（metal ions,or clusters）and multifunctional organic connectors.They are a class of materials with high specific surface area,adjustable pore size,and controllable surface function.MOFs have been widely used in catalysis,energy storage,separation,biomedicine,drug delivery,sensing,and environmental analysis.Pyrolysis of MOFs can not only maintain their original advantages,but also greatly improve their conductivity and increase the active sites.The carbon material prepared in this way is superior to the ordinary amorphous carbon material in terms of stability and physical and chemical properties.It is expected to show excellent catalytic performance and outstanding detection sensitivity in the construction of high-quality sensors when it is used to modify the electrode.In this paper,MOFs was used as a precursor and MOFs-derived carbon materials were prepared by pyrolysis to construct three kinds of sensors for electrochemical detection of dopamine（DA）,baicalin（Bn）and catechol（CC）.The main research contents are as follows:The bimetal MOF Co-ZIF-8 was used as the precursor,and the carbon-based material was obtained by limited carbonization assisted by F127,then etched in 2M hydrochloric acid,and finally the porous carbon Co-N-C with regular morphology and uniform size was obtained.The carbon material was used to modify the working electrode to construct an electrochemical sensor for dopamine detection,and the detection results had a low detection limit（3.89 n M）,a wide linear detection range（0.015-4μM）,and good stability.Co-N-C/GCE was used to detect the content of dopamine in bovine serum with good results.Bicone hexaprism Fe MOF（NH₂-MIL-88B）was synthesized by solvothermal method and pyrolyzed at 800℃for 2 h in nitrogen atmosphere to obtain Fe@C-800composite carbon.According to physical and electrochemical characterization,Fe@C-800 has higher specific surface area and porosity,and more dispersed active sites.Compared with bare glass,Fe@C-800/GCE has excellent electrocatalytic activity,higher sensitivity and excellent anti-interference ability for the detection of baicalin.The linear range is 4-700 n M,and the detection limit is 1.16 n M.The sensor was used for the determination of baicalin in the eye drops of baicalin urticaria baicalensis with satisfactory recovery.Sn MOF@GO composite was synthesized by in-situ synthesis method,and Sn MOF@GO-650 was obtained by carbonization of the composite directly at high temperature.SEM and TEM characterization showed that the composite was hollow cubic shape.Physical and electrochemical characterization showed that Sn MOF@GO-650 had a large specific surface area and excellent electron transfer kinetics.The Sn MOF@GO-650/GCE sensor was used to construct an electrochemical sensor for the detection of catechol by modifying the working electrode.The detection limit was as low as 33.32 n M,and the linear range was 0.2-28μM,with decent long-term stability and reproducibility.It can be used for the detection of actual sample tap water.