Preparation of graphene nanosheets by in-situ oxidation-exfoliation method

This paper aims at preparing graphene nanosheets from natural graphite by in-situ exfoliation during oxidation and intercalation when forming graphite intercalation compounds (GICs). The structure of GIC was characterized by X-ray diffraction (XRD). Graphene nanosheets were characterized by scanning electron microscopy (SEM) and transmission electron microscopy (TEM). The results show that graphene nanosheets of about 5 nm thickness are successfully prepared with natural flake graphite by this method. XRD results confirm that the layered structure of graphite is changed after the oxidation process, leading to the enlarged distance between layers. With the help of ultrasonic treatment, the layers of graphite can be further exfoliated. The ultrasonic treatment in combination with sodium dodecylsulfate (SDS) can effectively exfoliate the layers of GIC. The irregular two-dimensional structure of graphene layers is observed by SEM, and the graphene nanosheets of multi-layered structure are observed by TEM.