A FACILE AND CUT-RATE METHOD FOR SYNTHESS WATER SOLUBLE LARGE-SCALE GRAPHENE SHEETS BY LIQUID-PHASE EXFOLIATION OF GRAPHTE

Graphene known as a single layer of carbon atoms in hexagonally ordered cells has attracted a great deal of attention due to its magnificent physical, electronic and mechanical properties. In this paper we report on a chemical synthesis method successfully conducted to produce stack of graphite nanosheets with an appropriate dispersion characteristic in water. The synthesis of graphite nanosheets with controlled number of layers on a large scale was developed using chemical exfoliation by simply controlling the oxidation and exfoliation procedure. The graphene nano-sheets were synthesized by reducing a colloidal suspension of exfoliated graphite oxide. In the first step, a colloidal suspension graphite oxide was prepared by the application of a modified Hummer s method. Then, the graphite oxide was exfoliated into dispersed graphite oxide sheets in distilled water using the ultrasonic vibration to acquire graphene oxide nano-sheets. The graphene oxide nano-sheets were subsequently reduced with hydrazinehydrate at 100 °C with stirring for 24 h. followed by filtration and drying in vacuum. Graphene nanosheets were characterized by X-ray diffraction, Raman spectroscopy and FT-IR. It is found that the graphene nano-sheets are most likely formed with a few layer of graphene structurally oriented. The stack of graphene also exhibits excellent water dispersion and. The proposed method has also the attractive advantage of being rapidly able to produce a lot of graphene nano-sheets.