Preparation Of Functionalized Carbon Nanotube Composite Material And Their Application In Ratiometric Electrochemical Sensing

As an excellent one-dimensional carbon nanomaterial,carbon nanotubes have many excellent physical and chemical properties,such as high electrical conductivity,large surface area,good electrocatalytic activity,and good chemical stability,and thus can be a ideal material to construct different sensing platforms.Surface functionalization can improve the solubility of carbon nanotubes,and thus facilitate the purification of carbon nanotubes.In addition,surface functionalization can introduce new active sites,and is thus helpful for the the conjugation of carbon nanotubes with other materials.All these provide more possibilities for the construction of electrochemical sensing platforms.In this paper,we use different composites consisting of multi-walled carbon nanotubes(MWCNTs)and other electrochemically active materials.The transition metal oxide has a high specific surface area and good electrocatalytic activity,and the thionine dye material has good redox reversibility,fast electron transfer characteristics and high water solubility.All these materials can be used for the conjugation of multi-wall carbon nanotubes.The research content of the thesis is mainly divided into the following two aspects:(1)Acidified multi-walled carbon nanotubes were firstly prepared by using mixture of concentrated nitric acid and concentrated sulfuric acid(v:v=1:3),and the hierarchical manganese dioxide nanoflower(MnO2)was then obtained by electrodeposition method.The MnO2 nanoflower together with multi-walled carbon nanotubes is modified onto the electrochemically treated glassy carbon electrode(EPGCE)to obtain a MWCNTS/MnO2/EPGCE The MnO2 nanoflowers can be used as internal reference probes.The presence of MWCNTS not only enhances the electrochemical signal of the MnO2 nanoflowers,but also improve the electrochemical signal of the analyte dopamine(DA).The whole fabrication process for ratiometric electrochemical sensor for DA detection is simple and effective.(2)The first step in the preparation of the ratiometric sensor is to prepare acidified multi-walled carbon nanotubes with mixed acid,concentrated nitric acid:concentrated sulfuric acid(v:v=1:3),and then we use cyclic voltammetry to electropolymerize thionine on the surface of the glassy carbon electrode modified with acidified multi-walled carbon nanotubes.Such the pThi/MWCNTS/GCE can be used for the detection of butylhydroxyanisole(BHA).The pThi/MWCNTS composite has large specific surface area,good electrical conductivity,and high electrocatalytic ability,which can help improve the sensitivity of BHA detection and enhance the electrochemical signal of the internal reference probe The built-in correction function of pThi can significantly improve the accuracy and reliability of detection and analysis of BHA.