A method for enrichment of a mixture of graphene nanoplatelets (GNP) may include providing GNP into a column. The method may also include passing the GNP through an electrostatic field in a drift column to separate thinner GNP from thicker GNP to increase the content of the thinner GNP. The method may further include coupling a feeder to the drift column to accept the GNP and providing electrical charge to the GNP by the drift column with a charging module. The method may still further include generating the electrostatic field with an electrostatic field generator in the drift column to increase the content of GNP with smaller thickness.

Provided herein are methods, devices and systems for processing of carbonaceous compositions. The processing may include the manufacture (or synthesis) of oxidized forms of carbonaceous compositions and/or the manufacture (or synthesis) of reduced forms of oxidized carbonaceous compositions. Some embodiments provide methods, devices and systems for the manufacture (or synthesis) of graphite oxide from graphite and/or for the manufacture (or synthesis) of reduced graphite oxide from graphite oxide.

Provided herein are methods, devices and systems for processing of carbonaceous compositions. The processing may include the manufacture (or synthesis) of oxidized forms of carbonaceous compositions and/or the manufacture (or synthesis) of reduced forms of oxidized carbonaceous compositions. Some embodiments provide methods, devices and systems for the manufacture (or synthesis) of graphite oxide from graphite and/or for the manufacture (or synthesis) of reduced graphite oxide from graphite oxide.

A method for making a graphene nanoribbon composite structure includes providing a substrate including a plurality of protrusions spaced apart from each other. A graphene film is grown on a growth substrate, an adhesive layer is on a surface of the graphene film away from the growth substrate. After removing the growth substrate, the graphene film and the adhesive layer are cleaned with water or an organic solvent. The graphene film, the adhesive layer, and the substrate are combined and then are dried, so that a plurality of wrinkles are formed near the plurality of protrusions. The adhesive layer is removed, and after etching a surface of the graphene film away from the substrate, the graphene films except for the plurality of wrinkles are removed, to form a plurality of graphene nanoribbons.

A method for making a graphene nanoribbon composite structure includes providing a substrate including a plurality of protrusions spaced apart from each other. A graphene film is grown on a growth substrate, an adhesive layer is on a surface of the graphene film away from the growth substrate. After removing the growth substrate, the graphene film and the adhesive layer are cleaned with water or an organic solvent. The graphene film, the adhesive layer, and the substrate are combined and then are dried, so that a plurality of wrinkles are formed near the plurality of protrusions. The adhesive layer is removed, and after etching a surface of the graphene film away from the substrate, the graphene films except for the plurality of wrinkles are removed, to form a plurality of graphene nanoribbons.

Several variations of synthetic carbon materials are disclosed. The materials can assume a variety of properties, including high electrical conductivity. The materials also can have favorable structural and mechanical properties. They can form gas impenetrable barriers, form insulating structures, and can have unique optical properties.

Several variations of synthetic carbon materials are disclosed. The materials can assume a variety of properties, including high electrical conductivity. The materials also can have favorable structural and mechanical properties. They can form gas impenetrable barriers, form insulating structures, and can have unique optical properties.

Provided are graphene nanosheets having a polyaromatic hydrocarbon concentration of less than about 0.7% by weight. Also provided are Graphene nanosheets having a polyaromatic hydrocarbon concentration of about 0.01% to about 0.5%.

Provided are graphene nanosheets having a polyaromatic hydrocarbon concentration of less than about 0.7% by weight. Also provided are Graphene nanosheets having a polyaromatic hydrocarbon concentration of about 0.01% to about 0.5%.

Methods of making graphene oxide and reduced graphene oxide are provided. The methods can include a simple one-pot synthesis of graphene oxide from a purified coal powder using a mild oxidizing acid. The methods provide for an improved, more cost-effective, and simpler process than conventional methods such as Hummers methods. In some aspects, placing the purified coal powder in the mild oxidation atmosphere includes contacting the purified coal powder with a mild oxidizing acid such as nitric acid, nitrous acid, sulfuric acid, phosphoric acid, benzoic acid, or a combination thereof. In some aspects, the mild oxidizing acid consists essentially of nitric acid. Graphene oxides and reduced graphene oxides prepared by the methods are also provided.