A carbon nanotube aggregate includes a plurality of carbon nanotubes, a metal compound, and an oxide of the metal compound. The metal compound is contained in a space inside of each of the carbon nanotubes and/or in a space defined between the plurality of carbon nanotubes. When the metal compound is added inside the carbon nanotube aggregate, the metal compound is oxidized by reacting with oxygen or the like during or after a production process of the CNT aggregate, and the oxide is formed in the opening of the space to which the metal compound is added, so that the metal compound is capped with the oxide. Since the metal compound inside the CNT aggregate is shielded from the atmosphere, separation of the metal compound and reaction between the metal compound and oxygen and water in the atmosphere are suppressed, increasing heat resistance of the carbon nanotube aggregate.

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.

The embodiments of the present disclosure relate to a method, system and composition producing a magnetic carbon nanomaterial product that may comprise carbon nanotubes (CNTs) at least some of which are magnetic CNTs (mCNTs). The method and apparatus employ carbon dioxide (CO.sub.2) as a reactant in an electrolysis reaction in order to make mCNTs. In some embodiments of the present disclosure, a magnetic additive component is included as a reactant in the method and as a portion of one or more components in the system or composition to facilitate a magnetic material addition process, a carbide nucleation process or both during the electrosynthesis reaction for making magnetic carbon nanomaterials.

A carbon nanotube array constituted by large numbers of carbon nanotubes vertically aligned on a substrate is produced by supplying a carbon source gas into a reaction vessel having a hydrogen gas atmosphere, in which a substrate on which a reaction catalyst comprising fine metal particles is formed is placed; forming large numbers of vertically aligned carbon nanotubes on the substrate by keeping a reaction temperature of 500-1100° C. for 0.5-30 minutes; and heat-treating the carbon nanotubes by stopping the supply of the carbon source gas and keeping 400-1100° C. for 0.5-180 minutes in a non-oxidizing atmosphere.

A carbon nanotube aggregate includes a plurality of carbon nanotubes, a metal compound, and an oxide of the metal compound. The metal compound is contained in a space inside of each of the carbon nanotubes and/or in a space defined between the plurality of carbon nanotubes. When the metal compound is added inside the carbon nanotube aggregate, the metal compound is oxidized by reacting with oxygen or the like during or after a production process of the CNT aggregate, and the oxide is formed in the opening of the space to which the metal compound is added, so that the metal compound is capped with the oxide. Since the metal compound inside the CNT aggregate is shielded from the atmosphere, separation of the metal compound and reaction between the metal compound and oxygen and water in the atmosphere are suppressed, increasing heat resistance of the carbon nanotube aggregate.

The embodiments of the present disclosure relate to a method, system and composition producing a magnetic carbon nanomaterial product that may comprise carbon nanotubes (CNTs) at least some of which are magnetic CNTs (mCNTs). The method and apparatus employ carbon dioxide (CO.sub.2) as a reactant in an electrolysis reaction in order to make mCNTs. In some embodiments of the present disclosure, a magnetic additive component is included as a reactant in the method and as a portion of one or more components in the system or composition to facilitate a magnetic material addition process, a carbide nucleation process or both during the electrosynthesis reaction for making magnetic carbon nanomaterials.

The embodiments of the present disclosure relate to a method and apparatus for producing a carbon nanomaterial product (CNM) product that may comprise carbon nanotubes and various other allotropes of nanocarbon. The method and apparatus employ a consumable carbon dioxide (CO.sub.2) and a renewable carbonate electrolyte as reactants in an electrolysis reaction in order to make CNTs. In some embodiments of the present disclosure, operational conditions of the electrolysis reaction may be varied in order to produce the CNM product with a greater incidence of a desired allotrope of nanocarbon or a desired combination of two or more allotropes.

The embodiments of the present disclosure relate to a method and apparatus for producing a carbon nanomaterial product (CNM) product that may comprise carbon nanotubes and various other allotropes of nanocarbon. The method and apparatus employ a consumable carbon dioxide (CO.sub.2) and a renewable carbonate electrolyte as reactants in an electrolysis reaction in order to make CNTs. In some embodiments of the present disclosure, operational conditions of the electrolysis reaction may be varied in order to produce the CNM product with a greater incidence of a desired allotrope of nanocarbon or a desired combination of two or more allotropes.

The embodiments of the present disclosure relate to a method and apparatus for producing a carbon nanomaterial product (CNM) product that may comprise carbon nanotubes and various other allotropes of nanocarbon. The method and apparatus employ a consumable carbon dioxide (CO.sub.2) and a renewable carbonate electrolyte as reactants in an electrolysis reaction in order to make CNTs. In some embodiments of the present disclosure, operational conditions of the electrolysis reaction may be varied in order to produce the CNM product with a greater incidence of a desired allotrope of nanocarbon or a desired combination of two or more allotropes.

The invention has for its object to provide an aqueous solution for structural separation capable of acting on carbon nanotubes (CNTs) having a specific structure thereby separating them with high accuracy, a separation and recovery method capable of allowing the aqueous solution to act on CNTs having a specific structure thereby separating and recovering them, and CNTs obtained by the separation and recovery method. According to the invention, it is possible to separate CNTs having a specific structure with high accuracy by solubilizing lithocholic acid or a lithocolic acid isomer that has high hydrophobicity and is insoluble in water by itself, and a carbon nanotube obtained by using an aqueous solution containing lithocholic acid or a lithocholic acid isomer, each solubilized, as an aqueous solution for structural separation of CNTs.