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WO2001053199A2 - Nanotubes de carbone a paroi simple pour stockage de l'hydrogene ou formation de superamas - Google Patents

Nanotubes de carbone a paroi simple pour stockage de l'hydrogene ou formation de superamas Download PDF

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Publication number
WO2001053199A2
WO2001053199A2 PCT/US2001/001698 US0101698W WO0153199A2 WO 2001053199 A2 WO2001053199 A2 WO 2001053199A2 US 0101698 W US0101698 W US 0101698W WO 0153199 A2 WO0153199 A2 WO 0153199A2
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Prior art keywords
hydrogen
swnts
swnt
suspension
hno
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PCT/US2001/001698
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English (en)
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WO2001053199A3 (fr
Inventor
Anne C. Dillon
Thomas Gennett
Michael J. Heben
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Midwest Research Institute
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Priority to EP01916071A priority Critical patent/EP1248745A2/fr
Priority to JP2001553214A priority patent/JP2003520178A/ja
Priority to AU43139/01A priority patent/AU767499B2/en
Publication of WO2001053199A2 publication Critical patent/WO2001053199A2/fr
Publication of WO2001053199A3 publication Critical patent/WO2001053199A3/fr
Priority to US10/416,218 priority patent/US7160530B2/en

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    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B82—NANOTECHNOLOGY
    • B82Y—SPECIFIC USES OR APPLICATIONS OF NANOSTRUCTURES; MEASUREMENT OR ANALYSIS OF NANOSTRUCTURES; MANUFACTURE OR TREATMENT OF NANOSTRUCTURES
    • B82Y30/00—Nanotechnology for materials or surface science, e.g. nanocomposites
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B82—NANOTECHNOLOGY
    • B82Y—SPECIFIC USES OR APPLICATIONS OF NANOSTRUCTURES; MEASUREMENT OR ANALYSIS OF NANOSTRUCTURES; MANUFACTURE OR TREATMENT OF NANOSTRUCTURES
    • B82Y40/00—Manufacture or treatment of nanostructures
    • C—CHEMISTRY; METALLURGY
    • C01—INORGANIC CHEMISTRY
    • C01B—NON-METALLIC ELEMENTS; COMPOUNDS THEREOF; METALLOIDS OR COMPOUNDS THEREOF NOT COVERED BY SUBCLASS C01C
    • C01B3/00—Hydrogen; Gaseous mixtures containing hydrogen; Separation of hydrogen from mixtures containing it; Purification of hydrogen
    • C01B3/0005—Reversible uptake of hydrogen by an appropriate medium, i.e. based on physical or chemical sorption phenomena or on reversible chemical reactions, e.g. for hydrogen storage purposes ; Reversible gettering of hydrogen; Reversible uptake of hydrogen by electrodes
    • C01B3/001—Reversible uptake of hydrogen by an appropriate medium, i.e. based on physical or chemical sorption phenomena or on reversible chemical reactions, e.g. for hydrogen storage purposes ; Reversible gettering of hydrogen; Reversible uptake of hydrogen by electrodes characterised by the uptaking medium; Treatment thereof
    • C01B3/0021—Carbon, e.g. active carbon, carbon nanotubes, fullerenes; Treatment thereof
    • C—CHEMISTRY; METALLURGY
    • C01—INORGANIC CHEMISTRY
    • C01B—NON-METALLIC ELEMENTS; COMPOUNDS THEREOF; METALLOIDS OR COMPOUNDS THEREOF NOT COVERED BY SUBCLASS C01C
    • C01B32/00—Carbon; Compounds thereof
    • C01B32/15—Nano-sized carbon materials
    • C01B32/158—Carbon nanotubes
    • C01B32/168—After-treatment
    • C—CHEMISTRY; METALLURGY
    • C01—INORGANIC CHEMISTRY
    • C01B—NON-METALLIC ELEMENTS; COMPOUNDS THEREOF; METALLOIDS OR COMPOUNDS THEREOF NOT COVERED BY SUBCLASS C01C
    • C01B32/00—Carbon; Compounds thereof
    • C01B32/15—Nano-sized carbon materials
    • C01B32/158—Carbon nanotubes
    • C01B32/168—After-treatment
    • C01B32/174—Derivatisation; Solubilisation; Dispersion in solvents
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02E—REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
    • Y02E60/00—Enabling technologies; Technologies with a potential or indirect contribution to GHG emissions mitigation
    • Y02E60/30—Hydrogen technology
    • Y02E60/32—Hydrogen storage

Definitions

  • This invention relates to single-wall carbon nanotubes ("SWNTs”), and in particular to a method of processing SWNTs for use in hydrogen absorption or superbundle formation.
  • SWNTs single-wall carbon nanotubes
  • SWNTs As is well known in the materials science art, there has been interest in the mechanical, electrical, physical, and optical properties of SWNTs. This interest is not surprising when conside ⁇ ng the broad impact that these materials will make in the areas of science and technology, whether as applied in the form of super-strong composites, nanoelectronics, or to the safe storage of hydrogen which is vital in the development of hydrogen fuel cells or combustion engines. Indeed, the shape of SWNTs suggests that these composite materials would serve as an ideal hydrogen storage container. In order to further these applications, one must evaluate the intrinsic mechanical and electrical properties of SWNTs.
  • a distinct disadvantage of the prior art has heretofore been the inability in evaluating these properties when using the current synthesis and purification procedures, which result in SWNTs having a random o ⁇ entation, diameter, and length distribution.
  • many elect ⁇ cal and mechanical applications further require an orderly cutting or alignment of the individual nanotubes which comprise SWNT composite materials.
  • SWNT superbundles are also important because of the possibility of performing macroscopic analyses on well-defined samples. Of particular interest would be polarized Raman spectroscopy studies that would allow unambiguous assignment of observed spectral bands to specific types of SWNTs. Superbundle formation may also be a first step towards the production of longer. Control over the superbundle length and diameter at either the formation step or subsequently through the use of other means may provide a route to elect ⁇ cal connectors, or perhaps superbundle crystals and films that would be useful as hydrogen adsorbents or gas transport membranes.
  • Lithium doped carbon nanotubes were shown to adsorb hydrogen at ambient pressure to -20 wt% between 473-673 K while potassium doped samples adsorbed -14 wt% at room temperature. However, the potassium doped nanotubes were found to be oxidized rapidly upon exposure to a ⁇ r(5). Recently, acid treated large diameter (1.85 nm) SWNTs were shown to adsorb 4.2 wt hydrogen at room temperature and about 100 atm. The samples could be charged to 70% of the whole adsorption capacity in - 1 hr (6).
  • the present invention is intended to provide a method for processing SWNTs for use in high density hydrogen storage or in elect ⁇ cal or mechanical applications
  • the present invention provide a process of forming SWNT mate ⁇ als which are capable of at least 6-7 wt% hydrogen adsorption at ambient conditions
  • the invention provides a method of processing single-walled carbon nanotubes (SWNTs) in the formation of superbundles or for use in hydrogen storage, or both, comprising the steps of mixing a SWNT substrate in a solvent solution into a suspension, and agitating the suspension using an ultrasonic energy means Brief Description of Drawings
  • Figure la is a transmission electron microscope image of crude 4.2 W laser generated SWNT soot.
  • Figure lb is a transmission electron microscope image of a crude matenal which was refluxed for 16 h in 3M HNO 3 .
  • Figure lc is a transmission electron microscope image of pu ⁇ fied SWNTs produced by oxidizing the acid treated sample for 30 min. in air at 550 °C.
  • Figure Id is a transmission electron microscope image of pu ⁇ fied tubes at high magnification after annealing to 1500 °C in vacuum.
  • Figure 2a is a thermal gravimetnc analysis of 1-2 mg samples ramped from 25 - 875
  • Figure 3 is a Raman spectra obtained at 488 nm with a resolution of 2-6 cm ' for punfied, crude, and crude matenal which was refluxed for 16 h in 3M HNO-, ac ⁇ d.
  • the inset of the figure shows the region from 1200 - 1500 cm ' at an amplified intensity scale
  • Figure 4a is a is a transmission electron microscope image of purified tubes at high magnification.
  • Figure 4b is a is a transmission electron macoscope image of pu ⁇ fied tubes formed into "superbundles" of 0.5 to 2 microns in width
  • Figure 4c is a transmission electron microscopy image of a superbundle from figure 4b at higher magnification
  • Figure 5a is a transmission electron microscope image of SWNT superbundles extracted from water at low magnification illustrating the length of the fiber.
  • Figure 5b is a transmission electron microscope image of SWNT superbundles extracted from water at high magnification illustrating the width and dense packing of the superbundle.
  • Figure 6 is a transmission electron microscope image of punfied SWNTs following ultrasonication in 5M HNO The apparently endless ropes seen after pu ⁇ fication have been "cut” into compact bundles - 1 - 5 microns in length.
  • Figure 7 shows temperature programmed desorption spectroscopy data from both SWNTs and microcrystal ne graphite after a 10 min. hydrogen exposure at 500 torr. Both samples had been sonicated in dilute HNO 3 for 16 hours.
  • Figure 8a displays the hydrogen desorption signal from a HNO 3 sonicated SWNT sample following a 500 torr hydrogen exposure at room temperature. The sample remained at room temperature while the vessel was evacuated.
  • Figure 8b displays the CO 2 TPD signal after a hydrogen dose as in Figure 8a was followed by a 10 min. CO 2 dose at 500 torr.
  • FIG 8c displays the TPD signal for the hydrogen which also evolved along with the CO 2 shown in Figure 8b
  • Figure 9a is a Raman spectrum from pu ⁇ fied SWNTs.
  • Figure 9b is a Raman spectrum obtained after pu ⁇ fied SWNTs had been sonicated at
  • Figure 9c is a Raman spectrum obtained after pu ⁇ fied SWNTs were sonicated at 90 W/cm 2 in 5M HNO 3 for 4 hours and then degassed in vacuum to 973 K.
  • Figure 9d is a Raman spectrum obtained after pu ⁇ fied SWNTs were sonicated at 90 W/cm 2 in 5M HNO 3 for 4 hours, degassed in vacuum to 973 K, and then exposed to hydrogen at 500 torr.
  • Figure 9e is a Raman spectrum obtained after punfied SWNTs were sonicated at 90 W/cm 2 in 5M HNO-, for 4 hours, degassed in vacuum to 973 K, exposed to hydrogen at 500 torr, and then heated again to 973 K in vacuum. Best Mode for Carrying Out the Invention Unless specifically defined otherwise, all technical or scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs. Although any methods and mate ⁇ als similar or equivalent to those desc ⁇ bed herein can be used in the practice or testing of the present invention, the preferred methods and matenals are now desc ⁇ bed.
  • SWNT matenals were synthesized by a laser vaponzation method.
  • a single Nd YAG laser was used which produced gated laser light ranging in duration from 300 to 500 ns.
  • the gated laser light contained numerous short laser pulses ranging in duration from 5 to 15 ns.
  • the emission wavelength was 1064 nm and at an average power of 4 - 8 W.
  • Matenal was produced at rates of 75 - 150 mg / h
  • Targets were made by pressing powdered graphite doped with 0.6 at % each of Co and Ni in a 1 1/8 inch dye. Crude soot containing SWNTs was produced at 800 - 1300 °C, with 500 Torr Ar flowing at 100 seem.
  • TEM transmission electron microscope
  • the decomposition temperature (Td) is 735 °C, as determined by the derivative of the TGA curve, for the pure SWNTs displayed in Figure 2a.
  • the purified tubes are very stable presumably due to the lack of dangling bonds or defects at which oxidation reactions may initiate.
  • the final purity is estimated to be >98 wt % since ⁇ 1 wt % is consumed below 550 °C, and ⁇ 1 wt % remains above 850 °C.
  • the metal content of these pure SWNTs was measured to be below 0.5 wt % by ICPS.
  • TGA was also used to evaluate the crude and acid-refluxed materials to illuminate the key features of the purification process.
  • the data for the crude soot (Figure 2a) shows a slight increase in weight at low temperatures due to the oxidation of the Ni and Co metals.
  • the carbonaceous fractions begin to combust at -370 °C and are mostly removed by oxidation below 600 °C.
  • a small final weight loss at -650 °C can be attributed to oxidation of surviving SWNTs (-4 wt %).
  • the majority of SWNTs in the crude soot are combusted along with the other carbonaceous materials at lower temperatures.
  • the weight remaining at 875 °C corresponds to the weight expected for the oxidized metals ( ⁇ 8 wt %).
  • the acid treatment not only removes the metal but also produces carboxyl, aldehyde, and other oxygen - containing functional groups on the surfaces of the non-nanotube carbonaceous fractions.
  • the coating is extremely hygroscopic and reactive towards oxidation, enabling efficient punfication.
  • the TGA data was adjusted for the dry-weight lost du ⁇ ng reflux so that the y-axis represents the wt % remaining of the initial crude matenal
  • the data for the 4 and 16 h refluxes completely overlay at temperatures above -450 °C, and a plateau associated with SWNT stability is observed at 540 °C and a SWNT content of 17 wt 7c
  • the data sets are virtually identical at the higher temperatures despite the difference in the matenal weights which were lost du ⁇ ng the refluxes. Since the SWNT content is determined to be the same in both cases, neither reflux consumes a significant number of tubes As discussed earlier, tubes are not consumed by oxidation below 550 °C.
  • SWNTs could be readily imaged and portions of tubes were observed to be sharply angled, cut and damaged.
  • the extended reflux digests most of the non-nanotube carbon and begins to attack the SWNTs.
  • These cut and defective tubes are more susceptible towards oxidation such that only -8 wt %, or ⁇ 50 % of the tubes known to be present, are found at the inflection point in the curve at 625 °C ( Figure 2b).
  • Raman spectroscopy further elucidates the HNO 3 reflux process.
  • the Raman spectra displayed in Figure 3 for punfied and crude mate ⁇ als both exhibit a strong feature at 1593 cm ! with shoulders at 1567 and 1609 cm ' as expected for the SWNT tangential C-atom displacement modes.
  • the broadened feature at 1349 cm ' in the crude spectrum indicates the presence of abnormalties and a contnbution from the disordered sp 2 carbon "D band" of non-nanotube graphite components, P.C. Eklund, J.M. Holden & R.A. Jishi, Carbon 1995, 33,959; Y Wang, D C. Als eyer & R.L., McCreedy, Chem. Mater.
  • the 16 h 3M HNO 3 reflux decreases the domain size of the disordered carbon and produces a uniform carbon coating on the SWNTs without damaging them
  • Our own temperature programmed desorption studies show that the nit ⁇ c acid reflux introduces reactive functional groups onto the surfaces of the non-nanotube carbon matenal These two effects serve to maximize the surface area of the nonnanotube carbon and provide for enhanced oxidation kinetics.
  • the pu ⁇ fied SWNT soots were mixed in a aqueous 5M HNO-, solution Using an ultrasonic probe, a concentrated ultrasonic energy was directed into the solution The resultant cavitation produced microscopic domains of extremely high temperature The combination of the ultra sonic energy, high temperatures, and oxidative strength of the HNO 3 solvent provided a reproducible cut and an increase in bundle size or both of the
  • SWNTs A hydrogen adsorption analysis for the SWNTs cut using the 5M HNO 3 solution demonstrated an extremely high SWNT hydrogen affinity, in the range of 7 % w/w
  • a single Nd.YAG laser(1064 nm) was employed to synthesize the carbon nanotubes from 1.2 at % metal doped (50:50 Co/Ni) pressed graphite targets.
  • the targets were placed in a quartz tube that was heated to a temperature of 1200 °C in a clam-shell furnace.
  • the laser power and beam size were adjusted to provide -20 J/pulse-cm 2 at a -450 ns pulse width.
  • An argon flow of 100 seem at 500 torr was maintained through the reaction vessel for the duration of the synthesis.
  • the raw soot was punfied by refluxing in 3M nit ⁇ c acid for 16 hr, filte ⁇ ng and washing with dio zed water on a polytetraflouroethylene (PTFE) filter, and then heating the obtained paper in air for 30 min at 550 °C.
  • PTFE polytetraflouroethylene
  • This procedure results in tubes of greater than 98 wt.% punty when target matenal is not sputtered and trapped in vaponzed soot.
  • a representative TEM image of the resultant pure tubes is shown in Figure 4a. The random onentation and small size of the long bundles are apparent.
  • the SWNTs exist as a random tangle because of the conditions under which they are synthesized and pu ⁇ fied.
  • the tubes are formed within the high temperature plasma generated by the laser stnking the graphite target, and their formation is rapidly quenched as the tubes diffuse out of the plasma plume.
  • the resulting SWNTs exist in small bundles and are accompanied by other graphitic and amorphous carbon fractions as well as metal nanoparticles.
  • the pu ⁇ fication process succeeds in removing the non-nanotube carbon fractions and the metals. However, the pu ⁇ fication process still results in a random onentation of tube bundles which have - 5 - 20 nm diameters.
  • a 1 0 mg sample of pu ⁇ fied SWNTs was placed in a cylinder containing 10 ml of deiomzed water or other polar hydrophihc solvents or solvent mixtures
  • a Heat Systems- Ultrasonics Inc. model W-220F Cell Disrupter was submersed into the solution and the power was slowly increased to 90 watts/cm 2 .
  • the ultrasonic agitation was continued for a maximum of 120 minutes Normally, SWNTs are not dissociated in aqueous solution without the use of surfactants With the use of the ultrasonic probe, however, the SWNT sample was almost immediately dispersed throughout the solvent.
  • SWNT matenal agglomerated in the solution when the ultrasonic agitation was turned off Gentle shaking of the solution redistnubbed the tube agglomerations into an apparently homogeneous suspension. If the sonicated solution was allowed to settle, a thin layer of SWNT superbundles were observed at the solvent interface. At this point the isolation of the superbundles was achieved via several different procedures and on a senes of substrates. For example, a TEM gnd could be used to lift off the SWNT interface layer to extract fibers. The resulting isolated SWNT superbundles were approximately 0.4 - 1 micron in diameter,
  • Figures 4b displays a TEM image of SWNTs on a gnd dipped into the film formed following sonication in a 50:50 methanol/water mixture.
  • the large superbundles are readily apparent, and it is clear that some of these superbundles are completely isolated.
  • An image of an isolated bundle at higher magnification is displayed in Fig. 4c.
  • the superbundle configuration probably a ⁇ ses from the minimization of the interactions between hydrophobic SWNT surfaces and the hydrophihc solvent maximizing the vVan der Waals interactions along the axial length of the tubes.
  • the extent of collapse of the superbundle into a tight bundle depends upon solvent composition.
  • Figure 5a displays a TEM image of a more collapsed bundle extracted from water.
  • the dense bundle is displayed at higher resolution in Figure 5b.
  • a single Nd:YAG laser (1064 nm) was rastered across 1.2 at % metal doped (50:50 Co/Ni) pressed graphite targets in a quartz tube that was heated to 1200sC.
  • the laser was operated at a frequency of 10 Hz, at -10-30 J/pulse-cm2 with an - 450 ns pulse width Argon flowing at 100 seem at 500 torr was maintained through the reaction vessel for the duration of the synthesis
  • the raw soot was punfied by refluxing in 3M nitnc acid for 16 hr, filtenng and washing with de-ionized water followed by air oxidation for 30 min at 825 K
  • the H 2 adso ⁇ tion capacity of vanous SWNT samples were probed by a previously desc ⁇ bed temperature programmed deso ⁇ tion (TPD) technique Dillon, A.C.
  • the hydrogen deso ⁇ tion signals from SWNTs were calibrated using known H 2 deso ⁇ tion signals from 0.3 - 1 mg samples of CaH 2 The calibration was confirmed by performing thermal gravimetnc analyses on a lmg SWNT sample charged with hydrogen The hydrogen wt% measured by the two different methods was within 10%
  • the sample was sonicated in dilute HNO 3 for 16 hrs and degassed to 825 K resulting in hydrogen adso ⁇ tion of 6.5 wt%.
  • the spectrum is characte ⁇ zed by two separate deso ⁇ tion signals peaked at 370 and 630 K indicating at least two unique hydrogen adso ⁇ tion sites.
  • the hydrogen corresponding to the signal peaked at 370 K could be evolved by holding the sample at room temperature overnight in vacuum. Holding the SWNT sample at 423 K for only 8 minutes also resulted in complete evolution from the low temperature site which corresponds to -2.5 wt%. In order to desorb all of the hydrogen from the higher temperature site it was necessary to heat the sample between 475-850 K.
  • Figure 7 also displays the hydrogen deso ⁇ tion signal from micro crystalline graphite following the same pre-treatment and H 2 exposure as the optimized SWNT sample.
  • the graphite sample apparently has two H 2 adso ⁇ tion sites that are very similar to the SWNT sample as there are two deso ⁇ tion peaks at -380 and 610 K It is interesting however that the graphite hydrogen adso ⁇ tion is only -19 % of the H 2 adso ⁇ tion observed for an SWNT sample of the same mass following the same preparation
  • FIG. 8b and c display TPD deso ⁇ tion signals of CO 2 and H 2 respectively when an identical hydrogen exposure was followed by a CO 2 exposure for 10 mm. at 500 torr.
  • the small CO 2 deso ⁇ tion signal peaked at 400 K demonstrates the existence of a small population of CO 2 adso ⁇ tion sites on the SWNT sample. Su ⁇ nsmgly, however the H 2 deso ⁇ tion signals are both shifted to higher temperature by - 50 K. It appears that the hydrogen does not begin to desorb from the SWNTs until a significant portion of the CO 2 has already evolved suggesting that the
  • CO in fact blocks the hydrogen deso ⁇ tion process.
  • the sample was exposed to CO 2 for 10 min at 500 torr at room temperature and then exposed to H 2 under the same conditions.
  • Subsequent TPD revealed only a CO 2 deso ⁇ tion signal, similar to that seen in Figure 8b with no hydrogen abso ⁇ tion, demonstrating that carbon dioxide completely blocks hydrogen adso ⁇ tion sites.
  • CO 2 also apparently "caps" the SWNTs upon exposure to air. Samples charged with hydrogen and exposed to atmosphere were shown to desorb first CO 2 and then H 2 several weeks later without a significant loss in the stored hydrogen. This effective "capping" of the SWNTs by CO 2 may prove significant to the commercial development of SWNTs for a hydrogen storage system.
  • Raman spectroscopy was employed to elucidate the mechanism of the unique room temperature hydrogen adso ⁇ tion on SWNTs.
  • Raman spectra were obtained using a 50 mW Ar ion laser (488 nm) with a resolution of - 4-6 cm '.
  • Figure 9 displays a senes of Raman spectra between 1500 - 1700 cm ' collected from SWNT samples throughout the pretreatment and H 2 adso ⁇ tion process.
  • the initial spectrum of the pu ⁇ fied SWNTs (Fig 9a) exhibits two strong features at 1597 and 1571 cm ' These features are slightly shifted from their charactenstic occurrence at 1593 and 1567 cm '.
  • Figure 9b displays the Raman spectrum of the punfied sample following sonication in 5M HNO 3 for 4 hr at 90 W/cm 2 .
  • the two features are now broadened and further shifted to 1599 and 1575 cm ' with their intensity quite dramatically reduced Following degassing m vacuum to 1000 K however the Raman intensity returns, and the features are shifted back to their charactenstic values of 1593 and 1567 cm ' (Fig. 9c).
  • Figure 93d reveals that subsequent exposure to H 2 at 500 torr again results in a loss in Raman intensity and a shift to 1596 and 1570 cm '
  • the intensity of the Raman signal is again restored by heating in vacuum to 1000K resulting in the evolution of the adsorbed hydrogen (Fig. 9e).
  • a similar somewhat less reversible loss in intensity and slight shifting was observed for features attnubbed to the radial breathing modes between 162-203 cm "1 .
  • the reversible shift to higher frequency in Raman spectral bands observed in Figure 9 is indicative of charge transfer to an acceptor species.
  • the SWNT punfication process results in some degree of intercalation and functionahzation as indicated by the deso ⁇ tion of NO, H 2 O, CO, CO 2 , H 2 and hydrocarbons versus heating in vacuum to -1500 K
  • the pu ⁇ fied sample had been annealed to 825 K in air This should result in the deso ⁇ tion of the H 2 O, CO 2 and NO species.
  • the deso ⁇ tion of chemisorbed hydrogen from pu ⁇ fied uncut SWNTs occurs between - 900-1500 K.
  • the chemisorbed hydrogen is acting as an electron acceptor and produces the shift in the Raman spectrum of the pu ⁇ fied SWNTs to 1597cm '. The further shift to 1599 cm ' following cutting the
  • SWNTs in HNO 3 is consistent with an increase in the chemisorbed hydrogen population
  • the broadening and dramatic loss in intensity indicates that the nit ⁇ c acid intercalation interferes with the resonance enhancement of the SWNT Raman modes.
  • the process is reversible, however, as indicated by the return of intensity and appearance of the Raman modes at 1593 and 1567 cm ' upon heating to 1000 K. At this temperature a significant portion of the chemisorbed hydrogen resulting from the punfication and cutting procedures has desorbed.

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Abstract

Cette invention concerne un procédé de traitement de nanotubes de carbone à paroi simple (single wall carbon nanotubes/SWNT) pour la formation de superamas ou pour le stockage de l'hydrogène, ou pour les deux. Ce procédé consiste à mélanger un substrat SWNT dans un solution de solvant pour obtenir une suspension, puis à agiter cette suspension par application d'énergie ultrasonique.
PCT/US2001/001698 2000-01-19 2001-01-17 Nanotubes de carbone a paroi simple pour stockage de l'hydrogene ou formation de superamas WO2001053199A2 (fr)

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EP01916071A EP1248745A2 (fr) 2000-01-19 2001-01-17 Nanotubes de carbone a paroi simple pour stockage de l'hydrogene ou formation de superamas
JP2001553214A JP2003520178A (ja) 2000-01-19 2001-01-17 水素の貯蔵またはスーパーバンドル形成のための単層カーボンナノチューブ
AU43139/01A AU767499B2 (en) 2000-01-19 2001-01-17 Single-wall carbon nanotubes for hydrogen storage or superbundle formation
US10/416,218 US7160530B2 (en) 2000-01-19 2002-04-04 Metal-doped single-walled carbon nanotubes and production thereof

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US17707500P 2000-01-19 2000-01-19
US60/177,075 2000-01-19

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WO2004113222A1 (fr) * 2003-06-17 2004-12-29 Future Camp Gmbh Procede pour stocker de maniere reversible de l'hydrogene atomique sur/dans un micromateriau et/ou un nanomateriau carbone, et dispositif de stockage d'hydrogene
US7704480B2 (en) 2005-12-16 2010-04-27 Tsinghua University Method for making carbon nanotube yarn
US8246874B2 (en) 2005-12-02 2012-08-21 Tsinghua University Method for making carbon nanotube-based device

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JP5330034B2 (ja) * 2008-03-13 2013-10-30 国立大学法人東北大学 カーボンナノチューブの評価方法

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JP2522469B2 (ja) * 1993-02-01 1996-08-07 日本電気株式会社 カ―ボン・ナノチュ―ブの精製法
JP3607782B2 (ja) * 1996-10-17 2005-01-05 東洋炭素株式会社 単層ナノチューブの分離・精製方法及び金属内包ナノカプセルの分離・精製方法
WO1998039250A1 (fr) * 1997-03-07 1998-09-11 William Marsh Rice University Fibres de carbone produites a partir de nanotubes en carbone a paroi simple
JP3049019B2 (ja) * 1998-09-11 2000-06-05 双葉電子工業株式会社 単層カーボンナノチューブの皮膜を形成する方法及びその方法により皮膜を形成された単層カーボンナノチューブ
KR100364095B1 (ko) * 1999-06-15 2002-12-12 일진나노텍 주식회사 탄소나노튜브의 대량 정제 방법

Cited By (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2003054921A (ja) * 2001-08-13 2003-02-26 Sony Corp カーボンナノチューブの精製、整列、及び準結晶化
WO2004113222A1 (fr) * 2003-06-17 2004-12-29 Future Camp Gmbh Procede pour stocker de maniere reversible de l'hydrogene atomique sur/dans un micromateriau et/ou un nanomateriau carbone, et dispositif de stockage d'hydrogene
US8246874B2 (en) 2005-12-02 2012-08-21 Tsinghua University Method for making carbon nanotube-based device
US7704480B2 (en) 2005-12-16 2010-04-27 Tsinghua University Method for making carbon nanotube yarn

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AU767499B2 (en) 2003-11-13
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JP2003520178A (ja) 2003-07-02
EP1248745A2 (fr) 2002-10-16

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