Storage of Hydrogen at 303 K in Graphite Slitlike Pores from Grand Canonical Monte Carlo Simulation

Kowalczyk, Piotr; Tanaka, Hideki; Hołyst, Robert; Kaneko, Katsumi; Ohmori, Takahiro; Miyamoto, Junichi

doi:10.1021/jp0529063

Cited by 105 publications

(110 citation statements)

References 65 publications

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“…This result suggests that the relationship between the specific surface area and the hydrogen sorption uptake observed at cryogenic conditions does not hold at room temperature (Kowalczyk et al 2005;Wong-Foy et al 2006). One possible contributing factor to this could be that the trend established at 77 K uses the maximum hydrogen uptake which is not always reached at the studied temperature and pressure.…”

Section: Hydrogen Excess Adsorption At 298 Kmentioning

confidence: 90%

Hydrogen adsorption on microporous materials at ambient temperatures and pressures up to 50 MPa

2012

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High surface area microporous adsorbents are often proposed as potential hydrogen storage materials, although typically at 77 K and less than 5 MPa. In this study, we focus on conditions more suitable for automotive applications by investigating the storage capacities of microporous materials at 298 K and at pressures up to 50 MPa. In an effort to derive trends within and across material classes, we examined a wide range of materials with varying microstructures including the activated carbons AX-21, KUA-5, and MSC-30; a zeolite templated carbon; a hypercrosslinked polymer; and the Metal Organic Frameworks MOF-177, IRMOF-20, MIL-53, ZIF-8, and Cu 3 (btc) 2 . The peak excess adsorption of these materials ranged from 0.8-1.8 wt.%, although many did not reach their maximum capacity even at high pressures. However, the total volumetric storage gains over compressed hydrogen gas were quite low and, in many cases, negative. In addressing ambient temperature adsorption at significantly higher pressures than previously reported, our data confirms and extends the range of validity of several existing DFT calculations. Furthermore, our data suggest that, for both activated carbons and MOFs, factors other than specific surface area govern ambient temperature adsorption capacity. Contrary to some reports, the high fractions of sub-nanometer pores in some of the investigated MOFs did not appear to enhance the excess adsorption even at high pressures. For on-board applications with ambient temperature storage, significant enhancements to the attractive force at the materials' surface are required, beyond merely increasing specific surface area, or for MOFs, tuning of pore sizes.

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Section: Hydrogen Excess Adsorption At 298 Kmentioning

confidence: 90%

Hydrogen adsorption on microporous materials at ambient temperatures and pressures up to 50 MPa

2012

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“…For H 2 interactions with carbons more distant from boron usual values of LJ parameters have been used. 20 Feynman-Hibbs quantum corrections [21][22][23] were applied to all interactions. Figure 1 shows a map of minimum energy for H 2 adsorption over an infinite graphene surface with single boron atom substituted at the ͑0,0͒ position ͑left panel͒.…”

mentioning

confidence: 99%

Enhanced hydrogen adsorption in boron substituted carbon nanospaces

Firlej¹,

Roszak²,

Kuchta³

et al. 2009

The Journal of Chemical Physics

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Activated carbons are one of promising groups of materials for reversible storage of hydrogen by physisorption. However, the heat of hydrogen adsorption in such materials is relatively low, in the range of about 4-8 kJ/mol, which limits the total amount of hydrogen adsorbed at P = 100 bar to ϳ2 wt % at room temperature and ϳ8 wt % at 77 K. To improve the sorption characteristics the adsorbing surfaces must be modified either by substitution of some atoms in the all-carbon skeleton by other elements, or by doping/intercalation with other species. In this letter we present ab initio calculations and Monte Carlo simulations showing that substitution of 5%-10% of atoms in a nanoporous carbon by boron atoms results in significant increases in the adsorption energy ͑up to 10-13.5 kJ/mol͒ and storage capacity ͑ϳ5 wt % at 298 K, 100 bar͒ with a 97% delivery rate. Hydrogen is widely considered an essential part of our energy future despite the substantial difficulties derived from its low volumetric energy density. The development of a suitable material for reversible storage of hydrogen still remains a "grand challenge," 1,2 in particular for vehicular applications.1 Although some materials are potentially attractive, even the most promising candidates, nanoporous activated carbons, [3][4][5][6] have yet to meet the U.S. Department of Energy ͑DOE͒ 2010 targets ͑0.045 kg H 2 / kg system, 28 kg H 2 / m 3 system at room temperature for light-duty vehicles 7 ͒. Recent achievement in engineering carbons nanospaces resulted in preparation of very high surface area materials ͑Ͼ3000 m 2 / g͒ performing exceedingly well at cryogenic temperature ͑ϳ0.1 kg H 2 / kg system at P = 100 bar 6,8 ͒. However, the low heat of hydrogen physisorption on carbons ͑4-8 kJ/mol͒ results in low storage capacities at room temperature ͑ϳ0.02 kg H 2 / kg system at P = 100 bar͒. 5,6 The challenge is, thus, to find ways to increase the interaction of hydrogen and a carbon substrate.Boron-doped carbons are widely conjectured to be the suitable materials for hydrogen storage. It is believed that boron doping raises the binding energy to levels that would enable room temperature storage at moderate ͑Ͻ100 bar͒ pressures. This increase in the binding energy appears to be caused by boron acting as a p-type dopant, introducing electron deficiency in the graphite layer planes, thus lowering the Fermi level and increasing the surface polarizability.9,10 It is also possible that a partial charge transfer from the occupied orbital of H 2 to the empty p z orbital of B increases the interaction energy between H 2 and boron substituted carbon surface.11,12 So far, however, neither solid computational evidence ͑i.e., from first principles, beyond Ref. 11 for B-doped fullerenes͒ nor clear experimental evidence for enhanced hydrogen storage capacities of boron-doped carbons have been presented ͑to the best of our knowledge͒. Specifically, a major question is to what extent a single boron atom, substituted in graphitic carbon surface, creates high binding energies not o...

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“…The isosteric heat of adsorption for a fractional filling of less than 0.06 was 6 kJ/mol, which is much larger than the enthalpy of condensation at 20 K (0.904 kJ/mol). The observed value of 6 kJ/mol corresponds to the calculated value for a pore width of 0.7 nm using Grand Canonical Monte Carlo (GCMC) simulations (Kowalczyk et al 2005). Since there are serious difficulties with pore structure evaluation using nitrogen adsorption for ultramicropores with widths of less than 0.7 nm (Kobori et al 2009), the estimated pore width of 0.7 nm for ACM is plausible.…”

Section: Nanopore Structuresmentioning

confidence: 57%

Supercritical Hydrogen Adsorptivity of Amorphous Carbon Mesotubes

Kawase

Ohmori

Niimura

et al. 2011

Adsorption Science & Technology

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High-pressure adsorption isotherms of hydrogen onto amorphous carbon mesotubes (ACMs) prepared from fluorine polymer and onto activated carbon fibres (ACFs) were measured at temperatures of 77, 196 and 303 K, respectively, at pressures up to 10 MPa. The adsorption isotherms for ACMs and ACFs at 77 K exhibited maxima at 1 MPa (8.0 wt%) and 4 MPa (3.7 wt%), respectively, although both isotherms at 303 K were of the Henry type and both amounts of hydrogen adsorbed at 8 MPa were less than 0.3 wt%. The maximum hydrogen adsorption amount for ACMs per unit micropore volume as determined by N 2 adsorption was 10-times larger than that for ACFs. ACMs are different from ACFs in that they are thought to have specific ultramicropores, although characterization using high-resolution transmission electron microscopy, X-ray photoelectron spectroscopy and Raman spectroscopy showed that they possessed a nanographitic structure similar to that of ACFs.

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Storage of Hydrogen at 303 K in Graphite Slitlike Pores from Grand Canonical Monte Carlo Simulation

Cited by 105 publications

References 65 publications

Hydrogen adsorption on microporous materials at ambient temperatures and pressures up to 50 MPa

Hydrogen adsorption on microporous materials at ambient temperatures and pressures up to 50 MPa

Enhanced hydrogen adsorption in boron substituted carbon nanospaces

Supercritical Hydrogen Adsorptivity of Amorphous Carbon Mesotubes

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