Provided herein are graphene nanoribbons with high structural uniformity and low levels of impurities and methods of synthesis thereof. Also provided herein are graphene nanoplatelets of superior structural uniformity and low levels of impurities and methods of synthesis thereof. Further provided herein are mixtures of graphene nanoribbons and graphene nanoplatelets of good structural uniformity and low levels of impurities and methods of synthesis thereof. The method includes, for example, the steps of depositing catalyst on a constantly moving substrate, forming carbon nanotubes on the substrate, separating carbon nanotubes from the substrate, collecting the carbon nanotubes from the surface where the substrate moves continuously and sequentially through the depositing, forming, separating and collecting steps. Further processing steps convert the synthesized carbon nanotubes to graphene nanoribbons, graphene nanoplatelets and mixtures thereof.

A light absorber preform solution includes a solvent, a plurality of carbon nanotubes entangled with each other to form a network structure, and a plurality of carbon particles in the network structure. The plurality of carbon nanotubes and the plurality of carbon particles are in the solvent.

A light absorber preform solution includes a solvent, a plurality of carbon nanotubes entangled with each other to form a network structure, and a plurality of carbon particles in the network structure. The plurality of carbon nanotubes and the plurality of carbon particles are in the solvent.

A light absorber includes a plurality of carbon nanotubes and a plurality of carbon particles. The plurality of carbon nanotubes is entangled with each other to form a network structure. The plurality of carbon particles is located in the network structure.

Systems and methods are provided for production of carbon nanotubes and H.sub.2 using a reaction system configuration that is suitable for large scale production. In the reaction system, a substantial portion of the heat for the reaction can be provided by using a heated gas stream. Optionally, the heated gas stream can correspond to a heated H.sub.2 gas stream. By using a heated gas stream, when the catalyst precursors for the floating catalyst—chemical vapor deposition (FC-CVD) type catalyst are added to the gas stream, the gas stream can be at a temperature of 1000° C. or more. This can reduce or minimize loss of catalyst precursor material and/or deposition of coke on sidewalls of the reactor. Additionally, a downstream portion of the reactor can include a plurality of flow channels of reduced size that are passed through a heat exchanger environment, such as a shell and tube heat exchanger. This can provide cooling of the gas flow after catalyst formation to allow for carbon nanotube formation, while also reducing the Reynolds number of the flow sufficiently to provide laminar flow within the region where carbon nanotubes are formed.

Systems and methods are provided for production of carbon nanotubes and H.sub.2 using a reaction system configuration that is suitable for large scale production. In the reaction system, a substantial portion of the heat for the reaction can be provided by using a heated gas stream. Optionally, the heated gas stream can correspond to a heated H.sub.2 gas stream. By using a heated gas stream, when the catalyst precursors for the floating catalyst—chemical vapor deposition (FC-CVD) type catalyst are added to the gas stream, the gas stream can be at a temperature of 1000° C. or more. This can reduce or minimize loss of catalyst precursor material and/or deposition of coke on sidewalls of the reactor. Additionally, a downstream portion of the reactor can include a plurality of flow channels of reduced size that are passed through a heat exchanger environment, such as a shell and tube heat exchanger. This can provide cooling of the gas flow after catalyst formation to allow for carbon nanotube formation, while also reducing the Reynolds number of the flow sufficiently to provide laminar flow within the region where carbon nanotubes are formed.

The present invention relates to a bundle-type carbon nanotube which has a bulk density of 25 to 45 kg/m.sup.3, a ratio of the bulk density to a production yield of 1 to 3, and a ratio of a tap density to the bulk density of 1.3 to 2.0, and a method for preparing the same.

The present invention relates to a bundle-type carbon nanotube which has a bulk density of 25 to 45 kg/m.sup.3, a ratio of the bulk density to a production yield of 1 to 3, and a ratio of a tap density to the bulk density of 1.3 to 2.0, and a method for preparing the same.

A method of producing carbon nanotubes in a fluidized bed reactor includes preparing a carbon nanotube by supplying a catalyst and a carbon source to an interior of the fluidized bed reactor having an internal pressure of 0.5 barg to 1.2 barg (gauge pressure), thereby improving the yield and purity of carbon nanotubes.

A method of producing carbon nanotubes in a fluidized bed reactor includes preparing a carbon nanotube by supplying a catalyst and a carbon source to an interior of the fluidized bed reactor having an internal pressure of 0.5 barg to 1.2 barg (gauge pressure), thereby improving the yield and purity of carbon nanotubes.