An iron-free supported catalyst for the selective conversion of hydrocarbons to carbon nanotubes may include cobalt and vanadium as active catalytic metals in any oxidation state on a catalyst support comprising aluminum oxide hydroxide. The mass ratio of cobalt to vanadium is between 2 and 15; the mass ratio of cobalt to aluminum is between 5.8 10.sup.−2 and 5.8 10.sup.−1; and the mass ratio vanadium to aluminum is between 5.8 10.sup.−3 and 8.7 10.sup.−2. The present disclosure is further related to a method for the production of this iron-free supported catalyst and to a method for the production of carbon nanotubes using the iron-free supported catalyst.

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.

A system for measuring a concentration of lead in water includes a variable electrode having lead ionophore II and a reference electrode electrically connected to the variable electrode and having carbon nanotubes. A potentiometer is electrically connected to the variable and reference electrodes, and the potentiometer generates a signal reflective of the electrical potential between the variable and reference electrodes when the variable and reference electrodes are immersed in the water. A method for measuring a concentration of lead in water may include preparing a variable electrode having lead ionophore II and a reference electrode having carbon nanotubes. The method may further include electrically connecting a potentiometer with the variable and reference electrodes, immersing the variable and reference electrodes in the water, and generating a signal from the potentiometer reflective of the electrical potential between the variable and reference electrodes in the water.

A method for creating a carbon nanotube heater assembly includes creating a carbon nanotube heater with varying resistances and attaching the carbon nanotube heater to both carrier and encapsulating materials. Creating the carbon nanotube heater with varying resistances is accomplished by applying a carbon nanotube mixture to a substrate, adjusting the thickness or width of the carbon nanotube mixture, and drying the nanotube mixture.

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 nanocarbon separation device includes a separation tank that is configured to accommodate a dispersion liquid including nanocarbons, a first electrode that is provided at an upper part in the separation tank, a second electrode that is provided at a lower part in the separation tank, an evaluation unit that is configured to evaluate a physical state or a chemical state of the dispersion liquid, and a fractionation unit that is configured to fractionate the dispersion liquid based on the physical state or the chemical state.

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.

A method for creating a carbon nanotube heater assembly includes creating a carbon nanotube heater with varying resistances and attaching the carbon nanotube heater to both carrier and encapsulating materials. Creating the carbon nanotube heater with varying resistances is accomplished by applying a carbon nanotube mixture to a substrate, adjusting the thickness or width of the carbon nanotube mixture, and drying the nanotube mixture.