Electrochemical Sensor Based On MOFs Derived Carbon Based Materials

Metal-organic framework(MOFs)is a kind of crystalline hybrid porous coordination materials,which consists of metal ions as nodes and organic linkage groups.Because of its high porosity,large specific surface area and good structural stability,it is widely used in energy storage,adsorption,catalysis,biological sensing and other fields.By high temperature pyrolysis,MOFs can be used as precursors to obtain carbon matrix composites with different morphologies,structures and compositions,including nitrogen and phosphorus doped carbon materials,metal nitrogen oxides doped carbon materials,and various one-dimensional and two-dimensional carbon materials,etc.Compared with gas chromatography,fluorescence and colorimetric methods,electrochemical sensing has the advantages of high sensitivity,simple operation,short response time,good selectivity and on-line analysis,and has broad application prospects in food safety,environmental monitoring and other fields.The performance of electrochemical sensors generally depends on the properties of electrode modified materials,and some MOFs-derived carbon-based materials have good conductivity,adsorption capacity and electrochemical catalytic performance,so they are expected to be used in the construction of electrochemical sensors.In this paper,a series of carbon matrix composites derived from MOFs were successfully prepared and used in electrode modification to prepare an ultra-sensitive electrochemical sensor for the detection of flavonoids and biological small molecules in real samples.The specific content is described as follows:The precursor of Ce-MOF material was prepared by the traditional solution method,and the Ce-MOF-700 carbon based material was carbonized at 700°C,and the OH-Ce-MOF-700 was obtained by further acidification.Through SEM,EIS and other physical and electrochemical characterization methods,it is proved that the prepared OH-Ce-MOF-700 has a regular morphology,good electrical conductivity and electrocatalytic performance.A high performance electrochemical sensor was prepared by coating OH-Ce-MOF-700 drops on the glassy carbon electrode.The detection limits were 0.04?M,the recoveries were 93.9%-100.7%,and the relative standard deviations(RSD)were 0.11-0.21%.The results showed that the response signal was linear between0.1-1.3?M and 1.3-5.2?M.The results showed that the method was effective in detecting dopamine in bovine serum.ZIF-67 was synthesized by traditional solution method and carbonized at 800°C for two hours to obtain Co₃O₄@N-CNTs composite material.Then,it was combined with the amino-functionalized graphene quantum dots(NH₂-GQDs)with excellent dispersion property to solve the problem of poor dispersion of composite material.A highly sensitive electrochemical sensor for the detection of luteolin was obtained by dropping Co₃O₄@N-CNTs/NH₂-GQDs onto a glassy carbon electrode.Under the optimized conditions,the linear range of detection was 0.5-100 n M and 100-1000 n M,and the detection limit was up to 0.1 n M.It was applied to the detection of luteolin in actual chrysanthemum samples with good results.ZIF-8/Na Cl composites were synthesized in situ by salt template method.After carbonization at 650°C,Na Cl was removed with 1M sulfuric acid solution,and finally Zn O nanosheets(Zn O-CNSs)with large specific surface area were obtained.The MWCNTs-COOH/Zn O-CNSs/GCE sensor was prepared by dropping carboxylated multi-walled carbon nanotubes(MWCNTs-COOH)onto the glassy carbon electrode and then electrodeposition of Zn O nanosheets.The linear range is as follows:30-738n M,the detection limit is 10 n M,it was used for the determination of catechins in tea with good results.