▎ 摘　　要

Graphene and few-layer graphene have been synthesized from expanded graphite under microwave irradiations in an aqueous ammonia solution. Yields as high as 8% have been obtained taking into account the precursor weight. The particle size is typically comprised between 0.2 and 0.5 mm with a graphene layer number not exceeding ten. Films have been realized by spin coating and their electrical conductivity strongly depends on the number of oxygenated groups, probably located at the edge of the graphene sheets. (C) 2011 Elsevier B.V. All rights reserved.