Hydrogen storage in different carbon nanostructures

Ritschel, M.; Uhlemann, Margitta; Gutfleisch, Oliver; Leonhardt, A.; Graff, Andreas; Täschner, Christine; Fink, J.

doi:10.1063/1.1469680

Cited by 177 publications

(67 citation statements)

References 11 publications

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“…Some of the recent papers report hardly any adsorption in the different carbon nanostructures, the maximum adsorption in some cases being lower than 1 wt%. 15,16 In view of the importance of the subject and also the wide differences amongst the various findings, we considered it important to carry out H 2 adsorption measurements systematically on well-characterized samples of carbon nanotubes and fibres prepared by different methods. We have, therefore, carried out measurements on SWNTs produced by the arcdischarge method, on MWNTs synthesized by arc-discharge and by the pyrolysis of acetylene over catalysts, on aligned multi-walled nanotubes obtained by the pyrolysis of organometallic precursors as well as carbon fibres.…”

Section: Introductionmentioning

confidence: 99%

Hydrogen storage in carbon nanotubes and related materials

Gundiah

Govindaraj

Rajalakshmi³

et al. 2002

J. Mater. Chem.

169

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Section: Introductionmentioning

confidence: 99%

Hydrogen storage in carbon nanotubes and related materials

Gundiah

Govindaraj

Rajalakshmi³

et al. 2002

J. Mater. Chem.

169

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“…Some time ago carbon nanotubes were suggested to be useful for storing hydrogen, but only ∼3 wt % storage has since been achieved (2)(3)(4). It has been shown that reaction of single-layer graphene with hydrogen atoms generates sp 3 C-H bonds on the basal plane and the reduced material gets dehydrogenated on photothermal heating (5).…”

mentioning

confidence: 99%

Chemical storage of hydrogen in few-layer graphene

Subrahmanyam¹,

Kumar²,

Maitra³

et al. 2011

Proc. Natl. Acad. Sci. U.S.A.

234

146

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Birch reduction of few-layer graphene samples gives rise to hydrogenated samples containing up to 5 wt % of hydrogen. Spectroscopic studies reveal the presence of sp 3 C-H bonds in the hydrogenated graphenes. They, however, decompose readily on heating to 500°C or on irradiation with UV or laser radiation releasing all the hydrogen, thereby demonstrating the possible use of few-layer graphene for chemical storage of hydrogen. First-principles calculations throw light on the mechanism of dehydrogenation that appears to involve a significant reconstruction and relaxation of the lattice.hydrogen storage | reversible hydrogenation S torage of hydrogen in a suitable solid matrix is a major challenge facing the scientific community (1). Some time ago carbon nanotubes were suggested to be useful for storing hydrogen, but only ∼3 wt % storage has since been achieved (2-4). It has been shown that reaction of single-layer graphene with hydrogen atoms generates sp 3 C-H bonds on the basal plane and the reduced material gets dehydrogenated on photothermal heating (5). Reaction of atomic hydrogen with graphene produces hydrogenated graphene giving rise to changes in electronic and phonon properties (6). Through such hydrogen loading, a tunable band gap can be induced in graphene (7). The nature of hydrogen in the hydrogenated samples or the amount of hydrogen uptake by graphene has not been delineated. It has been suggested that hydrogenation of graphene may be more feasible with multilayer graphene than that with single-layer graphene (8). In the light of these reports, we have carried out detailed studies on the reduction of few-layer graphene samples prepared by two independent methods (9, 10) and examined the structure and stability of the hydrogenated products. We have employed Birch reduction (11), which is widely used to hydrogenate sp 2 carbon-based materials; in the case of C 60 and C 70 , Birch reduction yields C 60 H 36 and C 70 H 30 , respectively (12, 13). We find that up to 5 wt % of hydrogen can be incorporated in few-layer graphenes by Birch reduction. The sp 3 C-H bonds formed by the reduction of fewlayer graphenes are broken on heating or on irradiation with ultraviolet or laser radiation releasing all the hydrogen. Such chemical storage of a substantial amount of hydrogen in graphene is indeed noteworthy. We have carried out first-principles calculations to understand the nature of hydrogen in reduced graphene. Results and DiscussionFew-layer graphene samples were prepared by the exfoliation of graphite oxide (EG) (9) and the arc evaporation of graphite under hydrogen (HG) (10). Atomic force microscopy (AFM) indicated that the average number of layers in EG and HG were 6-7 and 2-3, respectively (see Fig. S1). The Brunauer-EmmettTeller surface areas of EG and HG were 670 and 210 m 2 ∕g, respectively. We carried out Birch reduction of EG and HG with lithium in liquid ammonia (11)(12)(13). Elemental analysis of reduced EG (EGH) and HG (HGH) samples showed the hydrogen content to be around 5 wt % in the sample...

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“…This result is consistent with many experiments, which reported that SWNTs have a certain hydrogen storage capacity at low temperature, [13][14][15] but have very low hydrogen uptake capacity at room temperature. [8][9][10][11][12] For H 2 molecules adsorbed on defected SWNTs, the situation is very different. Figure 7 shows a H 2 molecule stably adsorbed on the defected ͑10,10͒ SWNT at 300 K. Figure 7͑a͒ shows the radial distance of the adsorbed H 2 molecule from the adsorbing site on a defected ͑10,10͒ SWNT, versus annealing time at temperature, T = 300 K. It is obvious that this H 2 molecule is vibrating around its equilibrium distance without the trend of escaping from the tube in the time scale studied.…”

Section: B Adsorption Energies and Electron Density Contours Around mentioning

confidence: 98%

“…[5][6][7] In contrast to these reported promising results, other experimental measurements gave very discouraging results of hydrogen storage capacity in all examined carbon nanostructures, including SWNTs and MWNTs at room temperature. [8][9][10][11][12] Hydrogen storage in carbon nanotubes at low temperature and high pressure may be more suitable for obtaining higher hydrogen storage capacity. Hydrogen adsorption capacity more than 8 wt % in purified crystalline ropes of SWNTs was observed at ϳ128 atm and at 80 K. 13 A storage capacity of more than 6 wt % at T = 77 K and pressure 1 -2 atm for hydrogen physisorbed on heavily processed ropes of SWNTs was also reported.…”

Section: Introductionmentioning

confidence: 99%

Enhancement of hydrogen physisorption on single-walled carbon nanotubes resulting from defects created by carbon bombardment

et al. 2005

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The defect effect on hydrogen adsorption on single-walled carbon nanotubes ͑SWNTs͒ has been studied by using extensive molecular dynamics simulations and density functional theory ͑DFT͒ calculations. It indicates that the defects created on the exterior wall of the SWNTs by bombarding the tube wall with carbon atoms and C 2 dimers at a collision energy of 20 eV can enhance the hydrogen adsorption potential of the SWNTs substantially. The average adsorption energy for a H 2 molecule adsorbed on the exterior wall of a defected ͑10,10͒ SWNT is ϳ150 meV, while that for a H 2 molecule adsorbed on the exterior wall of a perfect ͑10,10͒ SWNT is ϳ104 meV. The H 2 sticking coefficient is very sensitive to temperature, and has a maximum value around 70 to 90 K. The electron density contours, the local density of states, and the electron transfers obtained from the DFT calculations clearly indicate that the H 2 molecules are all physisorbed on the SWNTs. At temperatures above 200 K, most of the H 2 molecules adsorbed on the perfect SWNT are soon desorbed, but the H 2 molecules can still remain on the defected SWNTs at 300 K. The detailed processes of H 2 molecules adsorbing on and desorbing from the ͑10,10͒ SWNTs are demonstrated.

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Hydrogen storage in different carbon nanostructures

Cited by 177 publications

References 11 publications

Hydrogen storage in carbon nanotubes and related materials

Hydrogen storage in carbon nanotubes and related materials

Chemical storage of hydrogen in few-layer graphene

Enhancement of hydrogen physisorption on single-walled carbon nanotubes resulting from defects created by carbon bombardment

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