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