Cohesive carbon assemblies are prepared by obtaining a functionalized carbon starting material in the form of powder, particles, flakes, loose agglomerates, aqueous wet cake, or aqueous slurry, dispersing the carbon in water by mechanical agitation and/or refluxing, and substantially removing the water, typically by evaporation, whereby the cohesive assembly of carbon is formed. The method is suitable for preparing free-standing, monolithic assemblies of carbon nanotubes in the form of films, wafers, discs, fiber, or wire, having high carbon packing density and low electrical resistivity. The method is also suitable for preparing substrates coated with an adherent cohesive carbon assembly. The assemblies have various potential applications, such as electrodes or current collectors in electrochemical capacitors, fuel cells, and batteries, or as transparent conductors, conductive inks, pastes, and coatings.

High density films of semiconducting single-walled carbon nanotubes having a high degree of nanotube alignment are provided. Also provided are methods of making the films and field effect transistors (FETs) that incorporate the films as conducting channel materials. The single-walled carbon nanotubes are deposited from a thin layer of organic solvent containing solubilized single-walled carbon nanotubes that is spread over the surface of an aqueous medium, inducing evaporative self-assembly upon contacting a solid substrate.

A nanometer niobium carbide/carbon nanotube reinforced diamond composite and a preparation method thereof, belonging to the field of materials science. The nanometer niobium carbide/carbon nanotube reinforced diamond composite is composed of nanometer niobium carbide/carbon nanotube composite powders, matrix powders and diamond grains, wherein the nanometer niobium carbide/carbon nanotube composite powders are the composites of nanometer niobium carbide which are evenly distributed in the surface defects and interior of the carbon nanotube, the nanometer niobium carbide/carbon nanotube reinforced diamond composite is prepared by mixing the nanometer niobium carbide/carbon nanotube composite powders, matrix powders and diamond grains uniformly and sintering with a hot pressing technique.

A nanometer niobium carbide/carbon nanotube reinforced diamond composite and a preparation method thereof, belonging to the field of materials science. The nanometer niobium carbide/carbon nanotube reinforced diamond composite is composed of nanometer niobium carbide/carbon nanotube composite powders, matrix powders and diamond grains, wherein the nanometer niobium carbide/carbon nanotube composite powders are the composites of nanometer niobium carbide which are evenly distributed in the surface defects and interior of the carbon nanotube, the nanometer niobium carbide/carbon nanotube reinforced diamond composite is prepared by mixing the nanometer niobium carbide/carbon nanotube composite powders, matrix powders and diamond grains uniformly and sintering with a hot pressing technique.

A method for producing carbon nanotubes and/or fibers, such as carbon nanotubes, involves sparging a gas (such as carbon dioxide) through a liquid hydrocarbon (such as crude oil) in the presence of an effective amount of metal oxide particles (such as MgO, Al.sub.2O.sub.3, CeO.sub.2, and/or SiO.sub.2 nanoparticles having a size in the range from about 2 nm to about 10 microns, and which may have a bimodal particle size distribution) at a temperature in a range of between about 70 to about 350° C. to produce carbon nanotubes and fibers having a size range of from about 50 nm to about 20 microns.

A method of producing a composite product is provided. The method includes providing a fluidized bed of carbon-based particles in a fluidized bed reactor, providing a catalyst or catalyst precursor in the fluidized bed reactor, providing a carbon source in the fluidized bed reactor for growing carbon nanotubes, growing carbon nanotubes in a carbon nanotube growth zone of the fluidized bed reactor, and collecting a composite product comprising carbon-based particles and carbon nanotubes.

Embodiments of the present disclosure relate to methods and systems for providing an electrolysis reaction in a molten carbonate electrolyte to synthesize helical carbon nanostructures (HCNSs). The electrolyte, electrode composition, current density, temperature and additives all may have important roles in the formation of HCNS. With control of these parameters, a variety of specific, uniform high yield HCNS can be synthesized by molten carbonate electrolysis, according to embodiments of the present disclosure.

CNT foams and methods are provided. The methods may include forming, in a non-solvent liquid, a suspension of CNTs and particles of a pyrolytic polymer; removing the non-solvent liquid; and removing the particles of the pyrolytic polymer to produce a CNT foam having cells that at least substantially correspond to the dimensions of the particles of the pyrolytic polymer. CNT foams having porous structures also are provided.

CNT foams and methods are provided. The methods may include forming, in a non-solvent liquid, a suspension of CNTs and particles of a pyrolytic polymer; removing the non-solvent liquid; and removing the particles of the pyrolytic polymer to produce a CNT foam having cells that at least substantially correspond to the dimensions of the particles of the pyrolytic polymer. CNT foams having porous structures also are provided.

A nuclear fuel element for use in a nuclear reactor may include a plurality of metal fuel sheaths extending along a longitudinal fuel element axis and spaced apart from each other, the plurality of fuel sheaths comprising a first fuel sheath having an inner surface, an opposing outer surface and a hollow interior configured to receive nuclear fuel material. A carbon coating may be on the inner surface of the first fuel sheath. The carbon coating may include more than 99.0% wt of a carbon material including more than 20% wt of carbon nanotubes and less than about 0.01% wt of organic contaminants.