Hydrogen Storage in Single-Walled Carbon Nanotubes at Room Temperature

Liu, C.; Fan, Yueying; Liu, M.; Cong, Huai‐Ping; Cheng, Hui‐Ming; Dresselhaus, M. S.

doi:10.1126/science.286.5442.1127

Cited by 1,843 publications

(739 citation statements)

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“…In particular, when an electric field passes through a nanotube that is stood on its end, the sharp nanotube tip concentrates the electrons and rapidly projects them onto a target. 50 As circuit miniaturization progresses, SWNTs offer the attractive advantage that they can act as metallic nanowires that have the potential to significantly impact the fields of energy storage 64 and molecular electronics [65][66][67][68][69] ( Figure 1 -5). NDC is observed for metallic nanotubes at low electric fields, which is significant for electronic applications and holds general implications for high-current applications based on 1D materials.…”

Section: Electronic Properties and Applicationsmentioning

confidence: 99%

Photophysics of Individual Single-Walled Carbon Nanotubes

2008

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Single-walled carbon nanotubes (SWNTs) are cylindrical graphitic molecules that have remained at the forefront of nanomaterials research since 1991, largely due to their exceptional and unusual mechanical, electrical, and optical properties. The motivation for understanding how nanotubes interact with light (i.e., SWNT photophysics) is both fundamental and applied. Individual nanotubes may someday be used as superior near-infrared fluorophores, biological tags and sensors, and components for ultrahigh-speed optical communications systems. Establishing an understanding of basic nanotube photophysics is intrinsically significant and should enable the rapid development of such innovations. Unlike conventional molecules, carbon nanotubes are synthesized as heterogeneous samples, composed of molecules with different diameters, chiralities, and lengths. Because a nanotube can be either metallic or semiconducting depending on its particular molecular structure, SWNT samples are also mixtures of conductors and semiconductors. Early progress in understanding the optical characteristics of SWNTs was limited because nanotubes aggregate when synthesized, causing a mixing of the energy states of different nanotube structures. Recently, significant improvements in sample preparation have made it possible to isolate individual nanotubes, enabling many advances in characterizing their optical properties. In this Account, single-molecule confocal microscopy and spectroscopy were implemented to study the fluorescence from individual nanotubes. Single-molecule measurements naturally circumvent the difficulties associated with SWNT sample inhomogeneities. Intrinsic SWNT photoluminescence has a simple narrow Lorentzian line shape and a polarization dependence, as expected for a one-dimensional system. Although the local environment heavily influences the optical transition wavelength and intensity, single nanotubes are exceptionally photostable. In fact, they have the unique characteristic that their single molecule fluorescence intensity remains constant over time; SWNTs do not “blink” or photobleach under ambient conditions. In addition, transient absorption spectroscopy was used to examine the relaxation dynamics of photoexcited nanotubes and to elucidate the nature of the SWNT excited state. For metallic SWNTs, very fast initial recovery times (300–500 fs) corresponded to excited-state relaxation. For semiconducting SWNTs, an additional slower decay component was observed (50–100 ps) that corresponded to electron–hole recombination. As the excitation intensity was increased, multiple electron–hole pairs were generated in the SWNT; however, these e−h pairs annihilated each other completely in under 3 ps. Studying the dynamics of this annihilation process revealed the lifetimes for one, two, and three e−h pairs, which further confirmed that the photoexcitation of SWNTs produces not free electrons but rather one-dimensional bound electron–hole pairs (i.e., excitons). In summary, nanotube photophysics is a rapidly developing area o...

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Section: Electronic Properties and Applicationsmentioning

confidence: 99%

Photophysics of Individual Single-Walled Carbon Nanotubes

2008

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“…In recent years, carbon materials such as carbon nanotubes (CNTs), carbon nanofibers and mechanically milled graphites have attracted attention owing to the availability of new carbon materials [1][2][3][4][5][6][7][8][9][10][11][12][13][14]. However, most studies concerning the hydrogen storage have been carried out at high pressures (1)(2)(3)(4)(5)(6)(7)(8)(9)(10)(11)(12)(13)(14)(15)(16) and low temperatures (80-133 K) in order to store molecular hydrogen by physisorption. It has been often reported that hydrogen storage by physisorption remains less than 4 wt% at room temperature and even high pressures [1,2].…”

Section: Introductionmentioning

confidence: 99%

“…However, most studies concerning the hydrogen storage have been carried out at high pressures (1)(2)(3)(4)(5)(6)(7)(8)(9)(10)(11)(12)(13)(14)(15)(16) and low temperatures (80-133 K) in order to store molecular hydrogen by physisorption. It has been often reported that hydrogen storage by physisorption remains less than 4 wt% at room temperature and even high pressures [1,2]. Although large hydrogen uptakes by CNTs have been reported [3,4], these results have not been easily reproduced.…”

Section: Introductionmentioning

confidence: 99%

Possibilities of atomic hydrogen storage by carbon nanotubes or graphite materials

Yoo

Habe

Nakamura³

2005

Science and Technology of Advanced Materials

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Atomic hydrogen storage by carbon nanotubes (CNTs) and highly oriented pyrolytic graphite (HOPG) has been studied using a flow catalytic reactor and an ultra-high vacuum surface science apparatus including scanning tunneling microscope (STM), respectively. Defect sites on CNTs as adsorption sites of atomic hydrogen are introduced by oxidation pretreatment using La catalyst. Pd catalysts are then deposited on CNT surfaces for dissociation of H 2 into atomic hydrogen, which spills over to the defect sites. In the best case, 1.5 wt% of hydrogen is stored in the defective CNT with Pd particles at 1 atm and 573 K. In temperature programmed desorption (TPD) experiments, H 2 starts to desorb at 700-900 K depending on the annealing temperatures of CNTs prior to hydrogen storage. On the HOPG surface, hot atomic hydrogen produced by dissociation of H 2 using tungsten wire desorbs from graphite terraces at 400-700 K, which is much lower than that on CNTs. It is possible that one can decrease the desorption temperature by changing the method of H 2 dissociation. q

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“…This has led to the consideration of converting to hydrogen energy from renewable sources [1]- [4]. Hydrogen is an energy carrier not an energy source and therefore, energy must be converted before hydrogen can be employed as carrier.…”

Section: Introductionmentioning

confidence: 99%

Heteroatom Doped Multi-Layered Graphene Material for Hydrogen Storage Application

Ariharan¹,

Viswanathan²,

Nandhakumar³

2016

Graphene

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A variety of distinctive techniques have been developed to produce graphene sheets and their functionalized subsidiaries or composites. The production of graphene sheets by oxidative exfoliation of graphite can be a suitable route for the preparation of high volumes of graphene derivatives. P-substituted graphene material is developed for its application in hydrogen sorption in room temperature. Phosphorous doped graphene material with multi-layers of graphene shows a nearly ~2.2 wt% hydrogen sorption capacity at 298 K and 100 bar. This value is higher than that for reduced graphene oxide (RGO without phosphorous).

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Hydrogen Storage in Single-Walled Carbon Nanotubes at Room Temperature

Cited by 1,843 publications

References 11 publications

Photophysics of Individual Single-Walled Carbon Nanotubes

Photophysics of Individual Single-Walled Carbon Nanotubes

Possibilities of atomic hydrogen storage by carbon nanotubes or graphite materials

Heteroatom Doped Multi-Layered Graphene Material for Hydrogen Storage Application

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