Unidym, Inc.

Carbon Nanotechnologies, Inc.

William Marsh Rice University

Samsung Electronics Co., Ltd.

Yuemei Yang

Martin Grosboll

Kenneth A Smith

Kenneth Odell McElrath

Eduardo Vega, Jr

Richard E Smalley

Robert H Hauge

Zhenning Gu

Jeffrey L Bahr

Wan-Ting Chiang

Xiaodong Hu

Aurelie Mayeux

Wilber Carter Kittrell

Kenneth O Mcelrath

A method for making carbon nanotube particulates involves providing a catalyst comprising catalytic metals, such as iron and molybdenum or metals from Group VIB or Group VIIIB elements, on a support material, such as magnesia, and contacting the catalyst with a gaseous carbon-containing feedstock, such as methane, at a sufficient temperature and for a sufficient contact time to make small-diameter carbon nanotubes having one or more walls and outer wall diameters of less than about 3 nm. Removal of the support material from the carbon nanotubes yields particulates of enmeshed carbon nanotubes that retain an approximate three-dimensional shape and size of the particulate support that was removed. The carbon nanotube particulates can comprise ropes of carbon nanotubes. The carbon nanotube particulates disperse well in polymers and show high conductivity in polymers at low loadings. As electrical emitters, the carbon nanotube particulates exhibit very low 'turn on' emission field.

Carbon nanotube particulates, compositions and use thereof

A method for separating single-wall carbon nanotubes from an aqueous slurry comprises adding a water-immiscible organic solvent to an aqueous slurry comprising single-wall carbon nanotubes, isolating at least some of the single-wall carbon nanotubes in the solvent, and removing the solvent from the single-wall carbon nanotubes to form dried single-wall carbon nanotubes. A spheroidal aggregate of single-wall carbon nanotubes is formed wherein the aggregate is approximately spherical and has a diameter in a range of about 0.1 and about 5 mm, and wherein the aggregate contains at least about 80 wt % single-wall carbon nanotubes. The spheroidal aggregates of single-wall carbon nanotubes are easily handled in industrial processes and are redispersable to single-wall carbon nanotubes and/or ropes of single-wall carbon nanotubes. This invention can also be applied to multi-wall carbon nanotubes.

Spheroidal aggregates comprising single-wall carbon nanotubes and method for making the same

A carbon nanotube material that comprises carbon nanotubes, a magnesia support and a catalyst metal can be purified by contacting it with a mixture comprising carbon dioxide and water. At least some of the magnesia support is reacted to form water-soluble compounds.

Process for purifying carbon nanotubes made on refractory oxide supports

A method for growing single-wall carbon nanotubes involves preparing a catalyst comprising catalytic metals, iron and molybdenum, and magnesium oxide support material and contacting the catalyst with a gaseous carbon-containing feedstock at a sufficient temperature and for a sufficient contact time to make single-wall carbon nanotubes. The weight ratio of iron and molybdenum can range from about 2 to 1 to about 10 to 1 and the metals loading up to about 10 wt % of the MgO. The catalyst can be sulfided. Methane is a suitable carbon-containing feedstock. The process can be conducted in batch, continuous or semi-continuous modes, in reactors, such as a transport reactor, fluidized bed reactor, moving bed reactors and combinations thereof. The process also includes making single-wall carbon nanotubes with catalysts comprising at least one Group VIB or Group VIIIB metal on supports such as magnesia, zirconia, silica, and alumina, where the catalyst is sulfided.

Method for making single-wall carbon nanotubes using supported catalysts

The present invention relates to an all gas-phase process for the purification of single-wall carbon nanotubes and the purified single-wall carbon nanotube material. Known methods of single-wall carbon nanotube production result in a single-wall carbon nanotube product that contains single-wall carbon nanotubes in addition to impurities including residual metal catalyst particles and amounts of small amorphous carbon sheets that surround the catalyst particles and appear on the sides of the single-wall carbon nanotubes and 'ropes' of single-wall carbon nanotubes. The purification process removes the extraneous carbon as well as metal-containing residual catalyst particles. The process comprises oxidation of the single-wall carbon nanotube material, reduction and reaction of a halogen-containing gas with the metal-containing species. The oxidation step may be done dry or in the presence of water vapor. The present invention provides a scalable means for producing high-purity single-wall carbon nanotube material.

Gas-phase process for purifying single-wall carbon nanotubes and compositions thereof

Growing community of inventors

Houston, TX, United States of America

Yuemei Yang