Construction And Application Of Electrochemical Sensors Based On MIL-101 Series Metal Organic Framework Nanomaterials

As a new force in porous materials,metal organic framework(MOF)materials have been widely used in catalysis,gas storage and separation,electrochemistry and other fileds due to their large specific surface area and large number of active sites.However,the direct use of MOF in electrochemical detection can not achieve good results because of their poor conductivity.By incorpation of noble metal elements,the detection sensitivity will be effectively improved by combining the good conductivity of noble metal nanomaterials with the super load capacity of MOF materials.In this thesis,two kinds of Materials of Institut Lavoiser-101(MIL-101)series organic metal frame materials were synthesized by hydrothermal method,and then gold nanoparticles were embedded by electrodeposition or double solvent method to construct biosensors for the detection of hydroquinone and dopamine.The main work is as follows:(1)Firstly,MIL-101(Cr)was synthesized by the hydrothermal method,and then it was tested by scanning electron microscope.Next,glassy carbon electrode deposited with MIL-101(Cr)(MIL-101(Cr)/GCE)was constructed by dripping the suspension of MIL-101(Cr)containing 0.1% chitosan on the surface of glassy carbon electrode(GCE).Subsequently,gold modified MIL-101(Cr)/GCE(Au/MIL-101(Cr)/GCE)was achived by electrodepositing gold nanoparticles on the surface of MIL-101(Cr)/GCE using chloroauric acid as ion source.The experimental conditions,such as p H,concentration of chlorogold acid,number of electrodeposition cycles and amount of drop coating,were optimized.The electrochemical properties of Au/MIL-101(Cr)/GCE were evaluated by cyclic voltammetry and electrochemical impedance spectroscopy.The experimental results showed that the fabricated biosensor had good electrocatalytic performance toward hydroquinone.Based on this,an electrochemical sensor was established for the detection of hydroquinone.The linear detection range and detection limit were 1-350 ?M and 0.3 ?M,respectively.Lastly,the sensor was applied to the detection of hydroquinone in actual water samples with a satisfactory recovery rate range from 96.5% to106.8%.(2)Firstly,MIL-101(Fe)was synthesized by the hydrothermal method.And then Au@ MIL-101(Fe)was obtained by double solvent method.Subsequently,Au/MIL-101(Fe)/GCE was prepared by dripping the suspension of Au@MIL-101(Fe)containing 0.1% chitosan on the surface of glassy carbon electrode.The electrocatalytic performance of the fabricated biosensor was studied by cyclic voltammetry and electrochemical impedance spectroscopy.The results showed that the sensor had good electrocatalytic performance toward dopamine.Based on this,an electrochemical sensor for the detection of dopamine was established.The linear detection ranges of dopamine were 5-100 ?M and 150-500 ?M,and the detection limit was 1.43 ?M.