Preparation Of Graphene/Poly(3,4-ethylenedioxythiophene)Hybrid And Its Several Applications In Electrochemical Fields

Poly(3,4-ethylenedioxythiophene)(PEDOT), belonging to the derivatives of polythiophene, is often characterized by high electrical conductivity, good thermal and chemical stability and fast electrochemical switching. Nowadays, lots of researches on PEDOT have been done, not only in supercapacitors but also many other fields.Graphene, a two-dimensional atomically thick crystal with carbon atoms arranged in a honeycomb lattice, was discovered by Geim et al in2004. It has attracted an enormous amount of interest from both theoretical and experimental scientists, as this material combines excellent mechanical, electrical properties with atomic thickness.This dissertation focuses on the studies of electrochemical synthesis of graphene/PEDOT hybrid and its applications in several electrochemical fields. The structures, morphologies and properties were characterized by using some techniques such as atomic force microscopy (AFM), scanning electron microscopy (SEM), fourier transform infrared (FTIR), cyclic voltammograms and so on. On basis of the above properties, we studied the performances of this hybrid as supercapacitor and electrochemical bisensor electrode material. The main results are summarized as follows:1. The application of graphene/PEDOT hybrid for supercapacitorsA novel high-performance supercapacitor electrode material based on graphene/PEDOT hybrid was synthesized via in situ electropolymerization of the3,4-ethylenedioxythiophene (EDOT) monomer on the graphene nanosheet in ionic liquid. The morphology characterization of the graphene/PEDOT hybrid by AFM and SEM demonstrated that the grain-shape PEDOT particles with the average size of80nmx40nmx2nm were attached to the graphene sheet’s surface tightly. The average specific capacitance of181F·g-1of the hybrid was obtained in the potential range from0to0.8V at1.0A·g-1by charge-discharge analysis and the hybrid showed good charge/discharge reversibility and electrochemical stability as supercapacitor electrode.2. The application of graphene/PEDOT hybrid for electrochemical sensorsFirstly, we investigated the application of the graphene/PEDOT hybrid electrode as an electrochemical sensor for detecting nitrite. The graphene/PEDOT hybrid showed excellent response in the entire [NaNO2] range0.01mM-1mM and the limit of detection was as low as0.17μM. Then, we used the graphene/PEDOT hybrid to immobilize hemoglobin and used this new biosensor for detecting hydrogen peroxide. The graphene/PEDOT hybrid showed quick response with the addition of hydrogen peroxide. When the concentration of hydrogen peroxide was in the range of20μM-800μM, the biosensor could response accurately. At the same time, the limit of detection was as low as15μM.