The Role of Water on the Oxidation Process of Graphene Oxide Structures

Abstract

Graphene oxide (GO) has recently attracted attention with its unique chemical and physical properties and serves as a raw material for graphene-based materials. GO has been produced for decades by the Hummers Method with the oxidation process of graphite. The properties and structure of GO are significantly affected by the production parameters of Hummers Method. In this study, the effect of the water content on the oxidation level of GO structure was investigated. GO was produced with different amounts of water in the oxidation stage of Hummers Method. The structural characterizations of produced GO were carried out by X-ray Diffraction Technique (XRD), Fourier Transform Infrared Spectroscopy (FTIR), X-ray Photoelectron Spectroscopy (XPS), Energy Dispersive X-ray Spectroscopy (EDS), UV-Visible Spectroscopy (UV-Vis) and Raman Spectroscopy. Additionally, morphological and thermal characterization of the produced GO samples were performed by Scanning Electron Microscopy (SEM) and Thermogravimetric Analysis (TGA)/Differential Thermal Analysis (DTA), respectively. According to XRD, FTIR, XPS, and EDS results, it was determined that the oxidation degree of GO decreased with increasing amount of water. Besides, it was revealed that the post-oxidation step generated more defects in the basal plane of graphene according to the results of the Raman Analysis. Also, it was observed that GO had a smoother surface and was found to have higher thermal stability with increasing amounts of water. The results show that the post-oxidation step reduces the oxidation degree of GO, increases the amount of the defect, provides a less wrinkled structure, and improves the thermal stability of GO.