The Study Of Synthesis And Characterization Of Graphene Via Electrochemical Exfoliation

Graphene, a two-dimensional structure material consisted of a single layer of carbon atoms, is a new type of carbon nanomaterials. Its discovery makes that the carbon materials established a complete system across the dimension, which is from zero to three dimension. Graphene has a lot of unprecedented properties, such as unusual electrical conductivity, outstanding strength, high transmittance in the visible region, superior thermal conductivity, high-specific surface area and so on. Accordingly, it has many potential applications in the fields of optoelectronic devices, nano-electronic devices, storage devices and composites materials. So, it has attracted tremendous attention in the field of physics, chemistry, materials, and electronics. The main contents of this paper are focused on the synthesis of graphene and corresponding characterization.Because the electrochemical preparation of graphene has many advantages, such as low-cost, eco-friendly and simple operation, in this paper, one-step electrochemical exfoliation and two-step electrochemical exfoliation were investigated to prepare the graphene. And the main research contents of this paper are as follows:Firstly, one-step electrochemical exfoliation under sulfuric acid solution is adopted to synthesize grapheme. The effects of electrolyte concentration and the electrolytic voltage on the final product are studied to obtain high-quality and high-yield graphene. The grapheme with a defect concentration of 0.52 is obtained, and the lateral size is up to 10 ?m.Secondly, in order to obtain high-quality graphene, one-step electrochemical exfoliation under alkaline conduction is explored. Different parameters have been optimized, such as the kinds of alkaline electrolyte, the electrolyte concentration and the processing time. And the grapheme with low defect concentration(0.05~0.14) is obtained.Thirdly, in order to solve the problem of the low product yield under alkaline electrolyte condition, a two-step electrochemical exfoliation for fabricating graphene is proposed, including a pretreatment in alkaline condition and a further exfoliation in acidic condition. By optimizing the pre-electrolysis treatment, the defect concentration of the final product is 0.29, which is much lower than that prepared by sulfuric acid solution only. Meanwhile, the product yield is substantially increased.