Investigation of graphene as an electrode for electroanalytical applications

The electrochemistry of multi layer graphene (MLG) and monolayer graphene have been investigated using macro and micro electrochemistry. Free standing electrodes of MLG were prepared by liquid exfoliation in N-Methyl-2-pyrrolidone and monolayer graphene on copper was prepared by chemical vapour deposition (CVD). Macro electrochemical measurements on MLG electrodes were performed however the response did not show the expected results due to a number of sample characteristics such as a high defect density, high resistance, rough surface and solvent contamination. Therefore, thin films were explored as optically transparent flexible electrodes. However, it was found that the optical and electrical properties of the material had limitations. The micro electrochemistry study also revealed that the porosity of MLG electrodes caused thin layer effects such as bulk depletion in the microdroplet electrochemical cells. The MLG was annealed to improve the electrode surface. The standard electron transfer rate constants were reported and it was shown that the kinetics of the annealed MLG was fast and reversible. Monolayer graphene on copper was also studied. The k0 were comparable since it were obtained using microdroplet technique and equal conditions.