Application Research Of Electrochemical Sensor Based On Composite Material Prepared By MIL-88

The metal-organic framework material has a nano-scale framework type regular pore structure,which has high crystallinity,larger specific surface area,higher porosity and small solid density,and there is a strong metal-ligand interaction.Its structure and function are also more diverse.Therefore,Fs materials are widely used in gas storage,adsorption and separation,drug sustained release and loading,optical,electrical,magnetic and catalytic reactions.However,due to poor hydrothermal stability and chemical stability,there is still no MOFs material that can fully meet the requirements of industrial production applications.In this paper,two kinds of MOFs were prepared by solvothermal method,and then carbon-based composite materials were prepared by calcination,thereby improving the water stability and electrocatalytic activity of MOFs,and constructing a new enzyme-free electrochemical sensor.The main research contents of this paper are as follows:?1?Preparation of iron/nickel@nitrogen nanotubes?Fe/Ni@NC-CNTs?composite material and construction of hydrazine hydrate?N₂H₄?enzyme-free electrochemical sensor.First,Fe/Ni-MIL-88 rod-shaped crystals were successfully prepared by solvothermal method,and then the mixture of rod-shaped crystals and melamine was calcined at high temperature to obtain Fe/Ni@NC-CNTs carbon-nitrogen doped composite material.The structure morphology and electrochemical performance of the product were characterized and analyzed by scanning electron microscope?SEM?,X-ray diffraction?XRD?,elemental analysis?EDS?,cyclic voltammetry?CV?,amperometric timing?i-t?and other methods.The experimental results show that the Fe/Ni@NC-CNTs composite has good electrocatalytic performance for N₂H₄:the linear range is 0.2?3.6 m M,the current response time is within 2 s,and the detection sensitivity is 181.939?A·m M^-1·cm^-2When the signal-to-noise ratio?S/N?is 3,the detection limit of Fe/Ni@NC-CNTs modified electrode for N₂H₄ is 0.8?M.Therefore,Fe/Ni@NC-CNTs composite materials can be practically applied to N₂H₄ detection in medicine,food and environment.?2?Preparation of carbon composite material iron/nickel@carbon?Fe/Ni@C?containing iron and nickel based on metal-organic framework and construction of L-cysteine?L-cys?enzyme-free electrochemical sensor.The prepared Fe/Ni-MIL-88rod-shaped crystal is directly calcined at high temperature to obtain the Fe/Ni@C composite material.The structure morphology and electrochemical performance of the product were characterized and analyzed by scanning electron microscope?SEM?,X-ray diffraction?XRD?,elemental analysis?EDS?,cyclic voltammetry?CV?,amperometric timing?i-t?and other methods.The experimental results show that the Fe/Ni@C composite has good electrocatalytic performance for L-cysteine:the the linear range is 0.02?0.28 m M,the current response time is within 3 s,and the detection sensitivity is 294.865?A·m M^-1·cm^-2.When the signal-to-noise ratio?S/N?is 3,the detection limit of Fe/Ni@C modified electrode for L-cysteine is 0.1765?M.Therefore,Fe/Ni@C composite materials have the potential for practical application in the field of cysteine electrochemical sensors.?3?Preparation of nitrogen-carbon composite material iron/palladium@nitrogen-carbon nanotubes?Fe/Pd@NC-CNTs?containing iron and palladium based on metal-organic framework and construction of enzyme-free electrochemical sensor for hydrazine hydrate?N₂H₄?.First,Fe/Pd-MIL-88 rod-shaped crystals were successfully prepared by solvothermal method,and then the rod-shaped crystals and melamine were mixed in equal amounts and calcined at high temperature to obtain Fe/Pd@NC-CNTs nitrogen-carbon composite material.Scanning electron microscope?SEM?,X-ray diffraction?XRD?,cyclic voltammetry?CV?,amperometric-timing?i-t?and other methods were used to characterize and analyze the product morphology and electrochemical performance.The experimental results show that the Fe/Pd@NC-CNTs composite has good electrocatalytic performanceFe/Pd@NC-CNTs composite When the diffusion coefficient is 4.26×10^-6 cm²·s^-1,the linear range is 0.05?6 m M,the current response time is about 1 s,the sensitivity is 114.443?A·m M^-1,and the signal-to-noise ratio?S/N?is 3.The detection limit of modified electrode to N₂H₄ was 0.12?M.The participation of precious metals can significantly improve the electrocatalytic activity of composite materials.Therefore,Fe/Pd@NC-CNTs composite material has certain application value in the field of N₂H₄ electrochemical detection.