Gram-scale production of graphene based on solvothermal synthesis and sonication

Carbon nanostructures have emerged as likely candidates for a wide range of applications, driving research into novel synthetic techniques to produce nanotubes, graphene and other carbon-based materials. Single sheets of pristine graphene have been isolated from bulk graphite in small amounts by micromechanical cleavage(1), and larger amounts of chemically modified graphene sheets have been produced by a number of approaches(2-7). Both of these techniques make use of highly oriented pyrolitic graphite as a starting material and involve labour-intensive preparations. Here, we report the direct chemical synthesis of carbon nanosheets in gram-scale quantities in a bottom-up approach based on the common laboratory reagents ethanol and sodium, which are reacted to give an intermediate solid that is then pyrolized, yielding a fused array of graphene sheets that are dispersed by mild sonication. The ability to produce bulk graphene samples from nongraphitic precursors with a scalable, low-cost approach should take us a step closer to real-world applications of graphene.