Investigation of The Effect of Vacuum Drying Conditions On Graphene Oxide Production

Abstract

Graphene consists of sp2 hybridized carbon (C) atoms arranged in a honeycomb shape as single layer. Graphene oxide (GO) structures have importance over graphene, because of hydrophobic nature of graphene, non-adjustable band gap, complex production processes and its production costs. GO structures are generally synthesized using graphite or carbon sources which are similar compounds compare to graphene. GO consists of both sp2 and sp3 hybridized C atoms to which functional groups are attached at the top and bottom of the layer. The mechanical, electronical and thermal properties of GO structures can be controlled during the production phase thanks to these oxygen-containing functional groups in their structure. These functional groups consist of oxygen (O) and hydrogen (H) elements in the form of carbonyl, hydroxyl, carboxyl or epoxide and they are highly dependent on the production method. Among the various methods for producing GO structures, the Hummers method stands out with its low cost, time efficiency and ease of parameter control. In this study, GO production was carried out by improved Hummers method, which consists of steps such as mixing with strong acids and oxidizing agents, washing with water and drying. The drying process, which is the last stage of production, directly affects the physical and chemical properties of the final product. Thus, the type and the amount of functional groups in the structure may change according to the drying method applied. In this study, the effect of drying, which is one of the Hummers method production parameters, on the oxidation level of the GO structure was investigated. For this purpose, GO structures were dried at different vacuum levels and atmospheric conditions. The produced GO structures were characterized using X-Ray Diffractometry (XRD) and Fourier Transform Infrared Spectroscopy (FTIR) devices. While XRD analysis showed the difference in phase structure, oxidation degree and interlayer distance between GO layers, FTIR analysis revealed the changes of functional groups in GO structures depending on drying conditions.