Synthesis of graphene nanosheets from petroleum asphalt by pulsed arc discharge in water

The synthesis of graphene nanosheets has been achieved by pulsed arc discharge in water with petroleum asphalt as a carbon source. The synthesized graphene nanosheets were examined by Raman spectroscopy, transmission electron microscopy, X-ray photoelectron spectroscopy, infrared spectroscopy and atomic force microscopy. The results indicate that most of as-synthesized graphene nanosheets have 2-5 layers, and small amounts of them have sheets in the range of 5-10 layers. The optical emission spectroscopy was used to monitor the arc discharge process, which indicates that the released hydrogen from asphalt may play a key role in the formation of graphene. (C) 2012 Elsevier B.V. All rights reserved.