Isothermal exfoliation of graphene oxide by a new carbon dioxide pressure swing method

Graphene oxide (GO) was prepared by a modified Hummers' method. GO was modified using a simple CO2 pressure swing technique to obtain exfoliated GO. The microcrystalline structures and morphologies were characterized using the X-ray diffraction and scanning electron microscope/transmission electron microscope measurements. The textural properties were investigated by N2 (77 K) adsorption/desorption isotherms. CO2 (298 K, 30 bar) and H2 (298 K, 100 bar) adsorption experiments were conducted to investigate their adsorption behaviors. The results indicated that the best sample had a specific surface area of 547 m2/g and total pore volume of 2.468 cm3/g. According to the results, CO2 pressure swing method can be used to increase the efficiency of exfoliation and expansion of the graphitic interlayers in GO.