WO2004096725A2 - Single-walled carbon nanotube-ceramic composites and methods of use - Google Patents
Single-walled carbon nanotube-ceramic composites and methods of use Download PDFInfo
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Definitions
- Carbon nanotubes are seamless tubes of graphite sheets with full fullerene caps which were first discovered as multi-layer concentric tubes or multi-walled carbon nanotubes and subsequently as single-walled carbon nanotubes in the presence of transition metal catalysts. Carbon nanotubes have shown promising applications including nanoscale electronic devices, high strength materials, electron field emission, tips for scanning probe microscopy, and gas storage.
- single-walled carbon nanotubes are preferred over multi-walled carbon nanotubes for use in these applications because they have fewer defects and are therefore stronger and more conductive than multi-walled carbon nanotubes of similar diameter. Defects are less likely to occur in single-walled carbon nanotubes than in multi-walled carbon nanotubes because multi-walled carbon nanotubes can survive occasional defects by forming bridges between unsaturated carbon valances, while single-walled carbon nanotubes have no neighboring walls to compensate for defects.
- Figure 1 shows a schematic drawing of several reactors which can be used to produce the products of the present invention.
- Figure 2 is a graph showing the concentration of CO 2 downstream of reactor B2 as a function of reaction time fortwo Co:Mo(1 :3)/silica catalysts (2% metal loading) with two different silica compositions (silica gel-60 and Hi-Sil ® -210). Reaction run at 850°C with a space velocity of 67, 000 h "1 .
- Figure 3 is a scanning electron micrograph of a nanotube-ceramic composite product showing bundles of SWNTs which remain intercalated among silica particles.
- Figure 4 is an I vs. V graph showing curves for composites prepared at different temperatures and H 2 concentrations.
- Figure 5 is a TEM image of prepared MCM-41 support material.
- Figure 6 is an XRD spectrum of MCM-41 prepared as in Figure 5.
- Figure 7 is an I vs. V graph showing curves for nanotube-ceramic composites prepared using various silica supports.
- Figure 8 is an I vs. V graph showing curves for Aerosil 380 nanotube-ceramic composites synthesized at 750°C and 850°C.
- Figure 9 is an I vs. V graph showing curves fortwo nanotube-ceramic composites with different metal loadings (2% and 6%).
- Figure 10 is an I vs. V graph showing curves for composites and SWNTs after different purification treatments.
- the present invention contemplates composites of single-walled carbon nanotubes (SWNTs) and a ceramic support (e.g., silica) comprising a small amount of catalytic metal, e.g., cobalt and molybdenum.
- the particle comprising the metal and ceramic support is used as the catalyst for the production of the single-walled carbon nanotubes.
- the nanotube-ceramic composite thus produced can be used "as prepared" without further purification providing significant cost advantages.
- the nanotube-ceramic composite has also been shown to have improved properties versus those of purified carbon nanotubes in certain application such as field emission.
- nanotube-ceramic composites may be produced based on support materials comprising AI 2 O 3 , La-stabilized aluminas, MgO and ZrO 2 , for example, which are suitable for a large variety of applications. When incorporated in polymeric matrices, these nanotube-ceramic composites may impart improved properties to the polymer.
- the catalysts which provide the ceramic component of the nanotube-ceramic composite of the present invention are prepared in one embodiment by impregnating the support component (e.g., silica) with different metal solutions of specific concentrations.
- the support component e.g., silica
- the Co:Mo/SiO2 catalysts are prepared by impregnating various silica supports with aqueous solutions of cobalt nitrate and ammonium heptamolybdate to obtain the bimetallic catalysts of the chosen compositions (see U.S.
- the present work has used four lab-scale reactors to study and optimize the reaction conditions for the Co:Mo/S ⁇ O 2 series ( Figure 1).
- the first reactor (A) consisted of a horizontal quartz tube of 1 inch in diameter, in which a ceramic boat with 0.5 g of calcined catalyst was placed. This is a typical reactor configuration commonly found in the literature about carbon nanotube synthesis.
- the second and third reactors (B1 and B2) were typical quartz fixed-bed reactors of 1/8 and 1/4 inch in diameter, respectively.
- Reactor B1 is loaded with 0.05 g of catalyst and it is considered a differential reactor when it is operated with a space velocity of 400,000 h "1 .
- Reactor B2 contained 0.5 g of the catalyst and was run with a space velocity of 67,000 h "1 .
- the fourth reactor (C) is a fluidized bed reactor.
- the catalyst is pre-reduced (e.g., by exposure to H 2 at 500°C) before the catalyst is exposed to reaction conditions.
- a carbon containing gas e.g., CO
- the catalyst Prior to exposure to a carbon containing gas (e.g., CO), the catalyst is heated in He up to the reaction temperature (700 ° C- 1050 ° C). Subsequently, a carbon-containing gas or gasified liquid is introduced. After a given reaction period that ranged from 1 to 600 min, the reactor was purged with He and cooled down to room temperature.
- the pretreatment of the catalyst may be done in a separate reactor, for example, for pretreatment of much larger amounts of catalyst whereby the catalyst can be stored for later use in the SWNT production unit. With this new methodology, a fluidized bed reactor can be kept operating continuously at the reaction temperature, thus eliminating the preliminary heating and cooling steps from the reaction process.
- the catalyst selectively produces SWNTs by the disproportionation of CO (decomposition into C and CO 2 ) in a preferred temperature range of 700-950 ° C (see U.S. Serial No. 10/118,834, which is hereby expressly incorporated by reference herein in its entirety).
- a synergism between Co and Mo is critical for the performance of this catalyst [4].
- these metals are not effective; they are either inactive (Mo alone) or unselective (Co alone).
- the catalyst is only effective when both metals are simultaneously present on the silica support with an intimate Co-Mo interaction. The basis for selectivity of the catalyst has been studied.
- This nucleation involves the disruption of Co atoms from its interaction with Mo oxide when the latter becomes carbidic. This disruption is followed by surface migration leading to agglomeration into mobile clusters that continue to grow under the bombardment of CO molecules. Some of these molecules decompose and begin to rearrange (nucleate) until a favorable configuration (embryo) is reached, which triggers the formation of the nanotube. When this embryo is formed, the subsequent incorporation of carbon and SWNT formation would proceed at a fast rate, perhaps only controlled by mass transfer. As a result, one may conclude that the growth of each tube is limited by nucleation, and after nucleation is completed, it is controlled by mass transfer.
- a fluidized-bed reaction system is a preferred alternative.
- much finer particles can be used than in a fixed bed reactor.
- particles as fine as powder can be used.
- agglomeration and sticking to the walls and between the particles can be avoided by well-established techniques such as stirring and vibration, which break interpaticle bonds and improve fluidizability.
- the particle size of the powders to be used fall under the type A category of the Geldart classification.
- Another method that could be used to minimize diffusional limitations that may occur during the growth of carbon nanotubes is the in-situ fragmentation of catalyst particles that expose a higher surface area to the gas phase as the reaction proceeds. This is a typical method used in polymerization processes to improve and modify the reaction kinetics [25].
- the in-situ fragmentation of the catalyst is obtained using a special support which might or might not need the use of special binders.
- This type of catalysts could be used in two ways. For example, as the nanotubes grow, the particles break exposing new surface and therefore increasing the total carbon yield obtained with such catalyst. Alternatively, a binder used in the support is disintegrated under the reaction conditions and a finer powder is generated in the reactor.
- the catalyst was first preheated to 950 ° C (thereby decreasing microporosity) and then cooled down to 750°C.
- the latest pretreatment resulted in a much better product with a quality parameter c of 0.83 while for the first case c was only 0.62 (the quality parameter c increases as the quantity of amorphous carbon in the product decreases).
- the quality parameter c increases as the quantity of amorphous carbon in the product decreases.
- no differences were observed in the diameter distribution of the SWNT produced and the carbon yield.
- the structure of the silica is compromised at a temperature as high as 950°C and therefore the micropores of the support tend to collapse.
- the average pre-treatment pore diameter of the silica-gel 60 is 6 nm.
- Single-walled nanotubes are not able to grow in pores that are much smaller than that and therefore those pores would lead to the formation of amorphous carbon.
- the production of amorphous carbon decreases and the quality of the material increases.
- the new SiO 2 used was a precipitated silica "Hi-Sil ® -210" (commercially available from PPG) which lacks microporosity.
- a catalyst comprising Co:Mo(1 :3) (2% metal loading) was prepared with the Hi-Sil ® -210 silica and three experiments were conducted running the Boudouard reaction for 2 hours at 750°C , 850°C and 950°C using the same procedure as previously described. A fourth reaction was run also at 750 ° C but used catalyst which had been pretreated with heating at 950°C.
- the results obtained for the quality parameter c and the carbon yield are summarized in Table 1 and were somewhat different than the results obtained for the silica-gel 60.
- the average diameter for SWNTs produced at a reaction temperature of 750°C is about 0.9 nm, while SWNTs produced at reaction temperatures of 850°C and 950°C have diameters of about 1.1 nm and about 1.4 nm, respectively.
- the nanotube-ceramic composites described herein may be formed from support materials comprising fumed silica nanoparticles (e.g., 10-20 nm in diameter), precipitated silica, silicas including silica gel, alumina (AI 2 O 3 ), La-stabilized aluminas, MgO (magnesium oxide), mesoporous silica materials including SBA-15 and Mobil Crystalline Materials (including MCM- 41), zeolites (including Y, beta, KL and mordenite), and ZrO 2 (zirconium dioxide).
- the catalysts in one embodiment, comprise cobalt and molybdenum (or other catalytic metals) and make up, preferably up to 20% wt of the ceramic catalyst particle.
- the ceramic catalyst may further comprise chromium, for example, or other metals including Fe, Ni, or W, or others as listed in U.S. Patent No. 6,333,016, or 6,413,487 or in U.S. Serial No. 60/529,665, each of which is hereby expressly incorporated herein in its entirety.
- Each nanotube-ceramic composite preferably comprises up to 50% carbon by weight, for example, 1 to 10% of the total weight of the composite.
- at least 50% of the SWNTs have outer diameters of 0.7 nm to 1.0 nm, more preferably at least 70%, and still more preferably at least 90%.
- At least 50% of the SWNTs have outer diameters of 1.0 nm to 1.2 nm, more preferably at least 70%, and most preferably at least 90%. In yet another embodiment, at least 50% of the SWNTs have outer diameters of 1.2 nm to 1.8 nm, more preferably at least 70%, and most preferably at least 90%.
- the support materials upon which the catalytic metals are disposed to form the metallic catalytic particles are not carbon nanotubes.
- the carbon nanotubes are produced only after the metallic catalytic particles are exposed to reaction conditions.
- the carbon nanotube-catalyst support compositions produced herein can be used, for example as, electron field emitters, fillers of polymers to modify mechanical and electrical properties of the polymers, fillers of coatings to modify mechanical and electrical properties of the coatings, fillers for ceramic materials, and/or components of fuel-cell electrodes. These of course are merely examples of how the compositions of the invention can be used and use is not limited to them. The present used are described in further detail below.
- FEDs field- emission displays
- CRT cathode ray tube
- nanotubes produced separately and later deposited on the cathode by techniques such as the screen- printing method.
- DNPs dielectric nanoparticles
- This development makes a perfect combination with the high quality nanotube- ceramic composites described herein.
- the nanotube-ceramic composites are particularly suitable for this application since the SiO 2 is in the form of (dielectric) nanoparticles and have shown excellent results in this regard (see Example I).
- nanotube-ceramic composites produced herein are shown in one embodiment in Figure 3.
- the nanosized particles of the silica support are physically spacing the bundles of nanotubes apart, which might be beneficial for field emission applications.
- the nanotube- ceramic composites of the present invention have at least two advantages over a purely physical mixture of purified nanotubes and SiO 2 .
- Single wall carbon nanotubes show unmatched electrical and mechanical properties, which make them good candidates to be incorporated into polymer matrices in order to obtain high-strength, conductive polymers.
- a good dispersion of the nanotubes in the polymer matrix is needed.
- this dispersion should contain individual nanotubes embedded in the polymer matrix.
- no technique developed until this moment has been entirely successful in achieving this order of dispersion.
- nanotube-ceramic compositions described herein as polymer filler provides the advantages of both nano-sized silica and SWNTs.
- dispersion techniques that have been developed for the incorporation of SiO 2 into different polymer matrices can still be applied to the nanotube-ceramic composition, therefore increasing, at the same time, the dispersion of the SWNTs.
- This dispersion can be carried out either in the molten state of the polymer or in solutions of the dissolved polymer in solvents of varying reactivity.
- Reactive solvents can be low-molecular weight thermo-setting resins which blend with the matrix polymer and may improve the processing conditions (e.g., blend viscosity and processing temperature).
- the surface chemistry of the SiO 2 can be easily changed for its incorporation in a specific polymer matrix by generating grafting sites, which can be used as anchoring sites for enhancement of polymer-filler adhesion and/or sites for starting in-situ polymerization.
- Uses as catalysts for in-situ polymerization [0053] A novel technique that we have invented for use in maximizing the dispersion of SWNT in polymer matrices is "in-situ-polymerization" (see U.S. Serial No. 10/464,041 , the entirety of which is hereby expressly incorporated by reference herein in its entirety).
- SWNT-polymer composites obtained by this technique are much better than those obtained for merely a physical mixture of the same polymer and the nanotubes [16, 17].
- a method that we used to incorporate and disperse SWNT in polymers was a technique called mini-emulsion polymerization, a well-established method for producing polymer particles with very narrow size distributions. This process has the advantage of requiring substantially less surfactant to stabilize the reacting hydrophobic droplets inside the aqueous medium than in conventional emulsion polymerization. It also eliminates the complicated kinetics of monomer transfer into micelles that takes place in the conventional emulsion polymerization.
- SWNT-filled polystyrene (SWNT-PS) and styrene-isoprene composites prepared by this method showed distinctive physical features such as: uniform black coloration; high solubility in toluene as well as in tetrahydrofuran (THF); and semiconductor to ohmic electrical behavior.
- In-situ-polymerization techniques can also be used to obtain good dispersions of the presently claimed nanotube-ceramic composites in different matrices.
- these nanotube-ceramic composites can be selectively tailored for in-situ-polymerization of specific polymers by adding an active agent to either the composite or the bare catalyst before the nanotubes are produced.
- SWNT/SiO 2 composite which has been doped with chromium to make it effective in in-situ-polymerization of ethylene.
- Polyethylene produced using Phillips Cr/SiO 2 catalysts represents 20% of the worldwide production of polyethylenes [18]. Since this catalyst needs to be activated under CO at high temperatures to be effective for polymerization[19], the present nanotube-ceramic composites doped with chromium can be already active for ethylene polymerization after the growth of the nanotubes by CO disproportionation. In fact, during the growth of SWNT, the catalyst is treated under pure CO at high temperatures.
- the chromium-doped nanotube-ceramic composite comprises an effective polymerization catalyst.
- Ceramics are traditionally hard but easy to break materials. Carbon nanotubes added to a ceramic material can greatly enhance its resistance to fracturing as well as increasing thermal and electrical conductivity of the ceramic. These new materials could eventually replace conventional ceramics or even metals in countless products. For example, scientists have mixed alumina powder with single-wall carbon nanotubes and then forced the particles together with a combination of heat, pressure, and pulses of electric current. Called spark- plasma sintering, the method operates at lower temperatures than the conventional sintering technique used in previous attempts to make nanotube-reinforced composites. When the researchers made a ceramic with nanotubes as 5.7% of its material, the product's fracture toughness increased to more than twice that of a pure-alumina ceramic.
- the basic parts of a fuel cell are an ion conducting electrolyte, a cathode, and an anode.
- a fuel such as hydrogen (or methanol) is brought into the anode compartment where it releases electrons and forms protons, which diffuse to the cathode compartment, where they react with oxygen and consume the electrons.
- the electrolyte acts as a barrier for gas diffusion, but allows ion transport.
- polymer electrolyte membrane (PEM) fuel cells are generally preferred for most portable systems. They operate by transporting hydronium ions through hydrated regions of a sulfonated polymer. Due to the high conductivity of the membranes they can operate at low temperatures ( ⁇ 100°C). Moreover, recent progress has allowed the use of proton-conducting membranes such as National (an ionomer) + silica + PW (a heteropolyacid based on phosphorus tungsten), which can operate 'water-free' and at low temperatures. In parallel with the development of electrolyte membranes, great attention is being paid worldwide to the development of improved electrodes to enhance reaction kinetics, decrease Pt loadings, and increase the tolerance to CO poisoning.
- PEM polymer electrolyte membrane
- the graphite nanofiber supported metal particles were observed to be significantly less susceptible to CO poisoning than the traditional catalysts. This improvement in performance was ascribed to specific crystallographic orientations that Pt would adopt when dispersed on the graphite nanofibers.
- Rajesha et al. [21] have found that a combination of Pt and W supported on multi-walled carbon nanotubes results in much more efficient electrodes for methanol fuel cells than those supported on Vulcan carbon, which was attributed to a much higher dispersion of the Pt metal.
- the operating principle of this device is that the interaction of the carbon nanotubes with the polymer allows charge separation of the photogenerated excitons in the polymer and efficient electron transport to the electrode through the nanotubes.
- the electrons travel through the nanotube length and then hop or tunnel to the next nanotube. This results in an increase in the electron mobility and balances the charge carrier transport to the electrodes.
- the researchers found that the composite's conductivity is increased by a factor of 10, indicating percolation paths within the material.
- This doping of P3OT polymer diodes with SWNTs also improves the device's photovoltaic performance, increasing the photocurrent by more than two orders of magnitude and doubling the open-circuit voltage.
- the presently-described nanotube-ceramic composites can be very useful for this application since a more controlled film preparation and polymer doping is required for further improvements in the performance of these devices.
- the presently-described nanotube-ceramic composites can help in achieving the required dispersion of SWNT in the polymer matrix used in this type of device.
- SWNTs obtained at higher temperatures show a broader diameter distribution centered at large diameters but bundles of smaller size [2].
- the influence of the dielectric structure on the field emission emission characteristics of the nanotube-ceramic composites was also studied.
- a series of different composites was prepared using different silica supports for the catalyst particle.
- the silicas include a silica gel 60 with an average pore diameter of 60 A, a Hi-Sil ® -210 silica with no microporosity and a surface area of 250 m 2 /g, and two different aerosols (Aerosil ® 90 and
- Aerosil ® 380 with specific surface areas of 90 and 380 m 2 /g and an average particle size of 20 and 7 nm, respectively.
- a series of MCM-41 were also specially synthesized to try to improve the field emission. Due to the highly ordered pore structure but the lower selectivity towards
- the MCM-41 silicas were prepared by mixing 100 g of CTAOH with 50 g of tetramethylammonium silicate and stirred for 30 minutes. Then 12.5 g of Hi-Sil ® -x was added to the solution, stirred for five minutes, and poured into an autoclave. The autoclave was placed in oven at 150°C for 48 hours. Upon removal, the autoclave was allowed to cool to room temperature. The solid was vacuum filtered with a B ⁇ chner funnel, washed with nanopure water, and dried under ambient conditions.
- the predried solid was calcined in air by heating from room temperature to 540°C over a twenty-hour period then soaked for two hours.
- the calcined samples were designated as MCM-41 -210, MCM-41 -233, and MCM-41-915 indicating the different Hi-Sil ® silicas used to start with.
- Figure 5 shows a TEM picture of the synthesized MCMs. The picture shows regular hexagonal array of uniform channels, which is typical for MCM-41. The average pore diameter in all the samples is about 40 A.
- XRD X-ray Diffraction Spectra
- the XRD patterns ( Figure 6) indicate that the samples exhibited hexagonal structures with a high degree of structural ordering, since all of the spectra featured three of ⁇ hkl) interplanar spacing associated with hexagonal lattice structure.
- the peaks seen in the spectra are narrow (100) peaks and well separated (110) and (200) reflections.
- the cylindrical unit cell parameter (a 0 ) is equivalent to the interplanar spacing of d 100l and the hexagonal unit cell parameter (a 0 ) is equivalent to the interplanar spacing of d 100 (2 ⁇ /3). From the interplanar spacing, the pore diameter of the samples was determined to be around 45 A, which is in good agreement with the TEM data.
- the same Co: Mo catalyst was prepared using the different supports and the nanotube-ceramic composites were prepared under reaction conditions at a temperature of 850°C. In this case, no hydrogen was included in the feed.
- the I vs. V curves for these samples are observed in Figure 7.
- the samples with the best field emission performance were those with the Aerosil ® silicas, which are fumed silicas with an average particle size in the nano-scale range.
- the Aerosil ® 90 sample which showed a slightly better performance than the Aerosil ® 380, has an average particle diameter of 20 nm, while the Aerosil ® 380 has an average particle size of 7 nm.
- the small difference in the field emission characteristics of these two samples appears to indicate that the average particle size of the fumed silica always in the 7 - 20 nm range is much less important than the general structure of the support.
- the sample made with the Hi-Sil ® -210 silica needed an electric field of 1.6 V/ ⁇ m more (4.02 V/um against 2.41 V/ ⁇ m) than the Aerosil ® 380 sample to achieve the same (4.76 mA/cm 2 ) current density.
- the structure of this silica is completely different since Hi-Sil ® -210 is a precipitated silica with a specific surface area of 150 m 2 /g.
- Hi-Sil ® -210 silica One important characteristic of the Hi-Sil ® -210 silica is its absence of microporosity.
- the silica gel 60 is highly microporous.
- the nanotube-ceramic composite prepared using this silica had poor field emission performance and did not achieve current densities higher than 0.12 mA/cm 2 .
- the MCMs prepared which have pore diameters in the order of 40 A showed the same poor behavior.
- Aerosil ® composites showed excellent performance achieving the targeted current density at very low electric field.
- another Aerosil ® composite was prepared, and the nanotube-ceramic composite was synthesized at 750°C.
- the comparison with that obtained at 850 ° C is showed in Figure 8. Again, the same trend is observed (better performance with higher synthesis temperatures).
- the composite produced at 850°C had a much better performance than that produced at 750°C.
- Aerosil ® composite synthesized at 850 ° C Another aspect of the Aerosil ® composite synthesized at 850 ° C that is important to note is the extremely low hysteresis observed in its I vs. V curve. No other material tested herein had shown such performance, with almost no deterioration of the sample after achieving current densities of almost 5 mA/cm 2 .
- the yield does not increase linearly with the metal content of the catalyst and therefore the efficiency of the metal decreases as shown in Table II.
- the metal efficiencies were 500wt% and 200wt%, respectively.
- the efficiency is low and only 147 moles of carbon are produced per mol of Co that is the active species, the efficiencies obtained using the present method of synthesis are much higher than those obtained by any other method.
- the highest efficiency reported by Ci, et al. [23] using the floating catalyst method with acetylene as the carbon source and Fe as the active catalyst was 3.25 moles of carbon per mol of Fe.
- the C/Fe ratio in the HipCO ® method is 10/1 [24].
- Table II also shows the quality parameter x (1-D/G) obtained from Raman spectra (514 nm laser) of the product obtained using the different catalysts (2 wt%, 6 wt% and 10 wt% metal loading). Although there is a clear trend where the quality parameter decreases as the metal loading is increased, it is important to remark that the quality of the SWNT does not differ much in this metal loading range and should not be a factor for the difference in field emission.
- the increase in metal/SWNT ratio produced a decrease in the field emission performance and therefore, the preferred nanotube-ceramic composite is that one with only 10% SWNT but the maximum SWNT/metal ratio.
- SWNT single-walled carbon nanotubes
Abstract
Description
Claims
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CA002523911A CA2523911A1 (en) | 2003-04-28 | 2004-04-28 | Single-walled carbon nanotube-ceramic composites and methods of use |
AU2004234395A AU2004234395A1 (en) | 2003-04-28 | 2004-04-28 | Single-walled carbon nanotube-ceramic composites and methods of use |
EP04760415A EP1626862A4 (en) | 2003-04-28 | 2004-04-28 | Single-walled carbon nanotube-ceramic composites and methods of use |
MXPA05011574A MXPA05011574A (en) | 2003-04-28 | 2004-04-28 | Single-walled carbon nanotube-ceramic composites and methods of use. |
JP2006513371A JP2006524631A (en) | 2003-04-28 | 2004-04-28 | Single wall carbon nanotube-ceramic composite and method of use |
BRPI0409874-9A BRPI0409874A (en) | 2003-04-28 | 2004-04-28 | nanotube polymer composite, ceramic composite material, fuel cell electrode, field emission material, field emission device, and carbon nanotube ceramic composite |
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Cited By (10)
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US7094386B2 (en) | 1999-06-02 | 2006-08-22 | The Board Of Regents Of The University Of Oklahoma | Method of producing single-walled carbon nanotubes |
US7354881B2 (en) | 1999-06-02 | 2008-04-08 | The Board Of Regents Of The University Of Oklahoma | Method and catalyst for producing single walled carbon nanotubes |
CN100436367C (en) * | 2005-03-25 | 2008-11-26 | 鸿富锦精密工业(深圳)有限公司 | Ceramic material and process for preparing same |
US7459138B2 (en) | 2000-06-02 | 2008-12-02 | The Board Of Regents Of The University Of Oklahoma | Process and apparatus for producing single-walled carbon nanotubes |
WO2010059027A2 (en) * | 2008-11-18 | 2010-05-27 | Universiti Sains Malaysia | A PROCESS FOR PRODUCING CARBON NANOTUBES (CNTs) |
US7816709B2 (en) | 1999-06-02 | 2010-10-19 | The Board Of Regents Of The University Of Oklahoma | Single-walled carbon nanotube-ceramic composites and methods of use |
WO2012006621A2 (en) * | 2010-07-09 | 2012-01-12 | The Regents Of The University Of Michigan | Carbon nanotube hybrid photovoltaics |
US8273486B2 (en) | 2009-01-30 | 2012-09-25 | Honeywell International, Inc. | Protecting a PEM fuel cell catalyst against carbon monoxide poisoning |
US20130029836A1 (en) * | 2009-02-13 | 2013-01-31 | Babcock & Wilcox Technical Services Y-12, Llc | Composite Materials Formed With Anchored Nanostructures |
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JP5078053B2 (en) * | 2004-11-29 | 2012-11-21 | 昭和電工株式会社 | Composition for heat conductive composite material containing carbon material and use thereof |
WO2010136899A1 (en) * | 2009-05-29 | 2010-12-02 | The Governors Of The University Of Alberta | Reinforced composites and methods of making and using thereof |
US10091916B2 (en) * | 2016-09-29 | 2018-10-02 | The Boeing Company | Fabrication of ceramic matrix composites with carbon nanotubes and graphene |
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US6346189B1 (en) * | 1998-08-14 | 2002-02-12 | The Board Of Trustees Of The Leland Stanford Junior University | Carbon nanotube structures made using catalyst islands |
US6333016B1 (en) * | 1999-06-02 | 2001-12-25 | The Board Of Regents Of The University Of Oklahoma | Method of producing carbon nanotubes |
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Cited By (16)
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US7816709B2 (en) | 1999-06-02 | 2010-10-19 | The Board Of Regents Of The University Of Oklahoma | Single-walled carbon nanotube-ceramic composites and methods of use |
US7354881B2 (en) | 1999-06-02 | 2008-04-08 | The Board Of Regents Of The University Of Oklahoma | Method and catalyst for producing single walled carbon nanotubes |
US7094386B2 (en) | 1999-06-02 | 2006-08-22 | The Board Of Regents Of The University Of Oklahoma | Method of producing single-walled carbon nanotubes |
US7459138B2 (en) | 2000-06-02 | 2008-12-02 | The Board Of Regents Of The University Of Oklahoma | Process and apparatus for producing single-walled carbon nanotubes |
US7357907B2 (en) | 2001-07-23 | 2008-04-15 | The Board Of Regents Of The University Of Oklahoma | Method for producing single walled carbon nanotubes |
CN100436367C (en) * | 2005-03-25 | 2008-11-26 | 鸿富锦精密工业(深圳)有限公司 | Ceramic material and process for preparing same |
GB2476916A (en) * | 2008-11-18 | 2011-07-13 | Univ Sains Malaysia | A process for producing carbon nanotubes (CNTs) |
WO2010059027A3 (en) * | 2008-11-18 | 2011-03-10 | Universiti Sains Malaysia | A PROCESS FOR PRODUCING CARBON NANOTUBES (CNTs) |
WO2010059027A2 (en) * | 2008-11-18 | 2010-05-27 | Universiti Sains Malaysia | A PROCESS FOR PRODUCING CARBON NANOTUBES (CNTs) |
US8273486B2 (en) | 2009-01-30 | 2012-09-25 | Honeywell International, Inc. | Protecting a PEM fuel cell catalyst against carbon monoxide poisoning |
US20130029836A1 (en) * | 2009-02-13 | 2013-01-31 | Babcock & Wilcox Technical Services Y-12, Llc | Composite Materials Formed With Anchored Nanostructures |
US8974719B2 (en) * | 2009-02-13 | 2015-03-10 | Consolidated Nuclear Security, LLC | Composite materials formed with anchored nanostructures |
US9878307B2 (en) | 2009-02-13 | 2018-01-30 | Consolidated Nuclear Security, LLC | Method of producing catalytic material for fabricating nanostructures |
WO2012006621A2 (en) * | 2010-07-09 | 2012-01-12 | The Regents Of The University Of Michigan | Carbon nanotube hybrid photovoltaics |
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AU2004234395A1 (en) | 2004-11-11 |
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