Production and characterization of graphene oxide and reduced graphene oxide with different oxidation times

ABSTRACT In this work aqueous dispersions of graphene oxide (GO) and reduced graphene oxide (rGO) were prepared in different oxidation times in order to verify the influence of the oxidation time on the characteristics of the final flakes. GO dispersions were prepared by the modified Hummers method, using the following oxidation times: 4 h; 1 day; 3 days; 7 days and 10 days. Afterwards the dispersions of GO were subjected to the reduction treatment with ascorbic acid, obtaining the rGO. Samples were characterized by Raman spectroscopy, X-ray photoelectron spectroscopy (XPS), scanning electron microscopy (SEM) and X-ray diffraction (XRD). Raman spectroscopy showed the variation of the intensity ratio between the D and G bands (ID / IG) as the oxidation time was increased. The XPS analysis indicated the alteration of the percentages of carbon (C) and oxygen (O). The SEM analysis correlated the morphology of the flakes with the increase of the oxidation time. Finally, with the aid of XRD, the variation of the interplanar distance was verified.

摘要
本研究通过设置不同氧化时长，制备氧化石墨烯（graphene oxide, GO）与还原氧化石墨烯（reduced graphene oxide, rGO）水分散液，以探究氧化时长对最终片材特性的影响。本研究采用改进的Hummers法制备氧化石墨烯分散液，设置的氧化时长分别为4小时、1天、3天、7天及10天。随后，以抗坏血酸作为还原剂对氧化石墨烯分散液进行还原处理，得到还原氧化石墨烯样品。采用拉曼光谱、X射线光电子能谱（X-ray photoelectron spectroscopy, XPS）、扫描电子显微镜（scanning electron microscopy, SEM）及X射线衍射（X-ray diffraction, XRD）对样品进行表征。拉曼光谱分析结果显示，随着氧化时长增加，D带与G带的强度比（ID/IG）发生变化。X射线光电子能谱分析表明，样品中碳（C）与氧（O）的占比发生改变。扫描电子显微镜分析结果表明，片材形貌随氧化时长增加呈现相应变化。最后，通过X射线衍射分析证实了片层间距的变化。