Chiral Detection Performance Of Ti₃C₂/MOFs Composite Photoelectric And Electrical Sensors

Chiral recognition is widely used in the food field,medical science,clinical analysis and other fields.The photoelectrochemical chiral sensor developed in recent years can make up for the shortcomings of chiral chromatography and has the advantages of small sample consumption,sensitivity and rapidity.Chiral photoelectric sensor selectively bonds with chiral substrate,which causes changes in electric signals such as potential,current and resistance,thus realising chiral recognition.Metal-organic skeleton compound（MOFs）is a new type of coordination polymer material with both inorganic and organic properties.It has the characteristics of a large specific surface area,controllable porosity and rich nano-channels.It has a wide application prospect in photoelectrochemical sensors,energy storage,molecular separation and other fields.However,MOFs materials have some shortcomings,such as poor conductivity,easy recombination of photogenerated electrons and holes,and significant charge transfer impedance,which limit their further application and popularisation.As a critical MXenes material,Ti₃C₂has the advantages of good conductivity,a small diffusion barrier and high volume capacitance.After being made into thin films,it can not only improve its electrochemical performance and mechanical stability but also provide more active sites with rich functional groups on the film surface.On this basis,it can be compounded with suitable MOFs materials,and the built-in electric field at the interface can reduce the photo-induced charge transfer impedance,improve the separation and transmission of carriers,and then improve the optical and electrochemical properties of the composite materials.The chiral properties of MOFs mainly come from the skeleton of ligands,but most ligands with chiral properties are expensive,and the synthesis process of MOFs is difficult to control and predict,so the application of MOFs is still a difficult problem.D-histidine（D-HIS）has low cost and good chiral detection performance.Moreover,MOFs materials can be modified by some simple methods,such as in-situ replacement and electrodeposition,to make MOFs have chiral detection capability.The article is mainly divided into the following three parts:（1）Preparation,properties and glucose detection mechanism of Ti₃C₂/NH₂-MIL-125 composite photoelectrochemical sensor.A Ti₃C₂film is synthesize by an electrophoretic deposition method,and then an NH₂-MIL-125 film is grown on that surface of the Ti₃C₂film by a spin coating method;and the influence of the thickness of the NH₂-MIL-125 film of the material on the in-detection performance is study by changing the spin coating times,XRD(X-Ray Diffraction,xps,scanning electron microscopy,transmission electron microscopy,The crystal structure,micro-morphology,optical properties and photoelectric properties were characterized by UV-Vis DRS（Ultra Violet-Visible Spectroscope Diffuse Reflections）and electrochemical test methods,and the detection mechanism was analyzed.The experimental results showed that the differential pulse voltammetry of the samples had a linear relationship with the concentration of glucose.When the glucose concentration was below 200μM,the linear relationship was current I（m A）=-3.86667×10^-8C（μM）+3.66×10^-4;When the glucose concentration was above 200μM,the linear relationship was current I（m A）=-4.03049×10^-8C（μM）+3.68268×10^-4.This indicates that the obtained Ti₃C₂/NH₂-MIL-125 photoelectrochemical sensor can realize sensitive detection of glucose.（2）A kind of Ti₃C₂/ZIF-67/D-His composite was designed.The Ti₃C₂film was immersed in the methanol solution of cobalt nitrate hexahydrate and dimethylimidazole to obtain the Ti₃C₂/ZIF-67 composite film.Finally,the composite film was immersed in the PBS buffer solution of D-His to obtain the Ti₃C₂/ZIF-67/D-His composite material.The crystal structure,micro-morphology,and photoelectric properties were characterized by X-ray diffraction（XRD）,X-ray photoelectron spectroscopy（XPS）,scanning electron microscopy（SEM）,transmission electron microscopy（TEM）,and electrochemical measurements.（3）Preparing a Ti₃C₂/NH₂-MIL-125 composite film by a spin coating method as a substrate;Then,by the electrodeposition method,D-His was epitaxially grown on the film surface to prepare Ti₃C₂/NH₂-MIL-125/D-His composite.by changing the deposition time,we found the optimal film thickness and explored the effect of the amount of D-His on the detection performance.XRD,FT-IR,SEM and TEM were used to analyze the phase structure and micro-morphology of the material.XPS was used to analyze the chemical state and the detection mechanism of the material was analyzed at last.