Electrochemical Behavior And Analytical Application Of Carbonaceous Electrodes Pretreated With High Voltage Electric Field

Carbon electrode is mainly composed of carbon materials.There are many kinds of carbon materials,such as graphene,carbon fiber,carbon nanotubes and porous activated carbon.Carbon electrodes have been widely used in the fields of biosensors,electrochemical catalysis and capacitors because of their excellent electrical conductivity,biocompatibility and electrocatalytic properties.However,the inert surface of carbon materials and the lack of active functional groups restrict the development of carbon electrodes.Therefore,it is of great significance to explore the surface activation method of carbon electrode to improve its surface activity and expand its application range.In this thesis,the method of improving the surface activity of carbon electrode based on high voltage electric field pretreatment was developed,and the electrochemical behavior and analytical characteristics of carbon electrode before and after pretreatment were characterized and studied.This thesis consists of three chapters:The first chapter is a review:firstly,the characteristics,classification,preparation and characterization methods of carbon electrodes and related applications are briefly introduced;then the theory,recent development and application of electric field are described;finally,the background and significance of this thesis are clarified.The second part is the study of electrochemical behavior and analytical performence of carbon fiber electrode(CFE)pretreated by high voltage electric field thermal effect.In this part,high voltage electric field was applied to the tip of CFE to realize the pretreatment.The surface structure and electrochemical properties of CFE were characterized by scanning electron microscopy(SEM)and electrochemical methods.The results showed that when the electric field was applied to the CFE,the tip of the carbon fiber was partially ionized,making it into a cone,and the surface of the carbon fiber formed smooth and even structure;at the same time,the surface of the CFE treated by the electric field showed better electrochemical reaction reversibility than that of untreated CFE.In addition,the possible mechanism of improving the surface activity of CFE by electric field was discussed,and the CFE pretreated by electric field was applied to the determination of dopamine and uric acid.The surface activation method of CFE proposed in this paper has the advantages of high space-time controllability,no additional reagent,simple and convenient operation.The third part is the preparation of carbon nanotube array modified electrode based on high voltage electric field guiding effect and its analytical application.When the electric field was applied to the carbon paste electrode,the thermal effect of the electric field made the paraffin melt.At the same time,the guiding effect of the electric field made the carbon nanotubes dispers in the paraffin move along the electric field and arrange directionally to form a carbon nanotube array perpendicular to the surface of the substrate electrode.The carbon nanotube array modified electrode was characterized by micro imaging,and electrochemistry.The results showed that the carbon nanotube array modified electrode has faster electron transfer rate and higher than the carbon nanotube drop coating modified electrode.Taking dopamine as an model,the analytical application of the carbon nanotube array modified electrode was discussed.This proposed method for fabricating of CNTs arry modfied electrode is simple and rapid.