Large-scale, substrate-free graphene, with few-layered sheets, is synthesized by the CVD of methane over cobalt supported on magnesium oxides at 1000 -C in a gas flow of argon. Typically, 50 mg of the few-layered graphene materials over 500 mg of the Co/MgO catalysts are synthesized under our experimental conditions. Randomly aggregated, thin, crumpled graphene sheets stacked closely together are produced. Both carbon (94.6 at.-%) and oxygen (5.4 at.-%) are present in the graphene sheets. The oxygen may originate from air adsorbed on the graphene sheets. Our results indicate the presence of localized sp 3 defects within the sp 2 carbon network and small sp 2 domains in the few-layered graphene particles.

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