Preparation And Application Of Electrochemical Sensors Based On MOFs And Its Derivatives Nanocomposites

Metal-Organic Framework?MOF?,because of its high porosity,large surface area,and high thermal/chemical stability,was widely applied for energy storage,catalysis,biomedicine and other fields.In recent years,functionalized MOFs had been a new research hotspot in electrochemical sensing applications.Compared with mass spectrometry,chromatography and other methods,electrochemistry was widely used in quantitative sensing of food,pharmaceuticals,small molecules,and environmental pollutants due to the superiority of low cost,high sensitivity,and easy operation.Currently,owing to the characteristics of poor conductivity and difficulty in dispersion,MOFs had become obstacle to the improvement of electrochemical performance.In order to solve these problems,this paper combines functionalized MOFs with electrochemical methods,to constructs several electrochemical sensors to detect small biological molecules,pesticide residues and antioxidant substances in actual samples.The main work contents contained as follows:1. To prepare HKUST-1 crystal with hydrothermal method.Functional Multi-walled carbon nanotube?MWCNTs-COOH?suspension was drop-coated on the surface of glassy carbon electrode?GCE?,then HKUST-1 deposited on the surface of MWCNTs-COOH/GCE by cyclic voltammetry method.This method solves the problems of poor water solubility and uneven dispersion of HKUST-1,especially the problem of MWCNTs-COOH falling off easily,thus improve conductivity and stablility.The response signal of MWCNTs-COOH/HKUST-1/GCE were linearly between 0.02-1.0?M and 1.0-15.0 m M,with detection limit of 0.0067?M.2. To prepare MOFs-derived materials?denoted as Cu O_x@m C?with high-temperature carbonization HKUST-1.The shape of pyrolysis products changed from previous regular octahedron to a uniform spherical structure,thus exposing more Cu active sites.These copper active sites could specifically bind to the target glyphosate?Gyp?to achieve quantitative detection.The electrochemical measurements demonstrated that the Cu Ox@m C/GCE displayed superior sensing performances,giving an ultralow detection limit of 7.69×10^-16M toward Gyp over the linear range of 1.0×10^-15to 1.0×10^-4M.Meanwhile,it had good reproducibility,anti-interference ability and feasibility in actual fruit sample testing.3. To prepare UIO-66 crystalline with structure similar to HKUST-1 by solvothermal method.Graphene oxide?GO?was firstly electrodeposited on the surface of GCE,and then was reduced to reductive graphene oxide?r GO?by cyclic voltammetry.Then,the UIO-66 suspension with recognition activity was drip-coated on the surface of r GO/GCE to construct a composite sensor UIO-66/r GO/GCE.Experiments have confirmed that this electrode can achieve sensitive detection of luteolin.It shows a good linear relationship at low concentration?0.001-0.05?M?and high concentration?0.05-20?M?,with a detection limit of 7.5×10^-4?M.Beside that,it also shows excellent recovery in real sample detection.