Preparation Of Bimetallic Organic Framework Materials And Electrochemical Applications

As a type of neurotransmitter present in the human brain,a series of changes in the concentration of dopamine(DA)in the human body are closely related to human health,so the accurate determination of the content of dopamine in the human body is increasingly being studied by researchers.Attention.The electrochemical analysis method has unique advantages in the detection of DA,and the electrode interface material plays a key role.It is very important to develop new electrode interface materials for the target substances to be tested.The selection of metal-organic frameworks(MOFs)can help modify the characteristics of the electrode surface interface and have a good electrochemical detection effect.Therefore,the application of metal organic framework materials to electrode interface materials has certain advantages and research significance.The characteristics of bimetallic MOFs are that they have two kinds of metal active sites,and they have rich catalytic active centers and ion distribution structures,which greatly improves the type of ionic active sites in the material.In view of this,this article uses hydrothermal synthesis method to use glutaric acid,3-(4-chlorophenyl)glutaric acid,3,3dimethyl glutaric acid as ligands,mainly nickel metal,A variety of bimetallic MOFs were prepared by adding different proportions of second metals(Fe,Co,Cu),and the structures,preparation method s,and electrochemical applications of these materials were studied.The main research contents are as follows:(1)9 types of bimetallic Ni/M-MOFs materials(M=Fe,Co,Cu,organic ligands are glutaric acid(L1)and 3-(4-chlorophenyl)pentane respectively)were synthesized by hydrothermal method Diacid(L2),3,3-dimethylglutaric acid(L3)),the effects of metal proportion,concentration,temperature and other factors on the product were discussed.The synthesis method was improved and 39 products were obtained.(2)The morphology and structure of bimetallic MOFs were characterized by X-ray diffractometer(XRD),Fourier-Infrared spectroscopy(FT-IR),scanning electron microscope(SEM),etc.The results show that the morphology of the product is largely affected by the ligand,using glutaric acid,3-(4-chlorophenyl)glutaric acid,3,3-dimethyl glutaric acid as the organic ligand The morphology of the bimetallic MOFs showed band shape,lamellar shape and cubic shape,respectively,and the color of the product gradually deepened with the increase of the proportion of another metal.The specific surface test shows that the strip-shaped bimetallic MOFs have a larger specific surface area,and also show relatively superior performance in subsequent electrochemical tests.This may be related to the specific surface area and pore size that can accelerate the electron transfer rate.Conducive to the transmission of electronics.Under the same ligand,when the metal ratio is 9:1 and the second metal is iron,the structural performance of the material is relatively the best,which is beneficial to the surface interface reaction,so the Ni/Fe91-L1,Ni/Fe91-L2,Ni/Fe91-L3 materials have good potential for electrochemical applications.(3)For the study of the electrochemical performance of bimetallic MOFs for the detection of DA,the three-electrode system was used to modify the prepared bimetallic MOFs on the surface of the working electrode by the drop coating method to study the cyclic voltammetry of the modified electrode(Cyclic voltammetry,CV)and the current-time curve(Amperometric it Curve,IT)and the redox behavior of DA molecules on the surface interface.The effects of other factors such as the concentration of DA in the system,different sweep rates,and peak potentials on the detection were discussed.The oxidation peak current of the bimetallic MOFs modified electrode is significantly higher than that of the electrode without modification,and it has a sensitive and rapid electrochemical response to DA.In addition,bimetallic MOFs modified electrodes were used to detect the electrochemical behavior of DA.The test results show that under the same ligand,the electrochemical performance of Ni/Fe bimetallic MOFs as electrode interface materials are better than Ni/Co and Ni/Cu bimetallic MOFs,wherein the ligand is glutaric acid Ni/Fe91-L1/GCE has the best electrochemical performance,has the advantages of high electrochemical stability and good selectivity,DA has a good correlation in the range of 7×10-6～7×10-2 μM(r=0.9918),detection limit It is 3.9×10-3μM(S/N=3),which can be used in the field of electrochemical detection.