Hydrogen adsorption and desorption by carbon materials

Kojima, Yoshitsugu; Kawai, Yasuhiko; Koiwai, Akihiko; Suzuki, Nobuaki; Haga, Tetstuya; Hioki, Tatsumi; Tange, Kyouichi

doi:10.1016/j.jallcom.2005.09.077

Cited by 82 publications

(45 citation statements)

References 39 publications

(52 reference statements)

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“…At 6.7 MPa, hydrogen uptake in MSC-30 was 3.1 mmol g -1 , consistent with reported values for MSC-30 to within 0.3 mmol g -1 . 65,66 This value was reproducible upon cycling to well within experimental error, to which we assign an upper bound of ±0.05 mmol g -1 . In Pt-MSC-30, low-pressure data showed a steep initial uptake of hydrogen between 0-0.01 MPa and then a similar constant slope region to MSC-30 between 0.04-2 MPa.…”

Section: Hydrogen Sorption Resultssupporting

confidence: 56%

Enhanced Hydrogen Dipole Physisorption, Final Report

Ahn

2014

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literature 9 . The surface excess can be depicted schematically as shown in Figure 4. Near the adsorbent surface, in the region labeled "adsorbed layer", the local adsorptive density is considerably higher than in the bulk gas phase. It is assumed that at a suitably large distance from the adsorbent surface, the adsorptive density decays back to a constant bulk density (bulk). This region is labeled as the "bulk gas". Important quantities for the adsorption model are defined in Table 1.The standard practice is to express adsorption as a Gibbs surface excess quantity. This is the amount of adsorptive which is present in the adsorbed layer in excess of the bulk gas density, indicated in Figure 4 by the dark gray region. Conveniently, the surface excess amount is the quantity which is measured in a standard volumetric measurement. The expression for the Gibbs surface excess amount is therefore Equation 3The surface excess amount n_is an extensive quantity. Typically, however, data are presented as a specific surface excess amount Equation 4where ms is the sorbent mass. 9 S. Sircar, Gibbsian surface excess for gas adsorption-revisited, Ind Eng Chem Res 38 (10), 3670-3682 (1999).

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Section: Hydrogen Sorption Resultssupporting

confidence: 56%

Enhanced Hydrogen Dipole Physisorption, Final Report

Ahn

2014

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“…The amounts of stored hydrogen at 77 K for all samples were largest in all obtained values. The same trend of hydrogen storage ability with temperature have been shown in other reports [4,21,22]. Figure 7 shows the maximum amount of stored hydrogen in the sample as a function of temperature.…”

Section: Resultssupporting

confidence: 83%

“…Carbon-based hydrogen storage materials, using nano-structured carbon materials [3], and porous carbon [4], have been reported. Especially, some reports indicated that the activated carbon having large specific surface area adsorbed 0.6-1.3 wt.% of hydrogen at room temperature.…”

Section: Introductionmentioning

confidence: 99%

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Effect of chemical species in alkali agents on pore structure at activated carbon of rice husks

Ono

Akasaka

Toda

et al. 2011

Trans. Mat. Res. Soc. Japan

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To understand effect of chemical reactions of the activation process on pore structures, the activated carbon materials were fabricated by two types of chemical agent for the activation process from rice husk ashes. NaOH and Na 2 CO 3 were used as a chemical agent. And their pore structure and hydrogen storage ability were estimated on temperature range from 77 to 298 K. The porous carbon activated by NaOH involved pores of 0.6, 1.1 and 1.5 nm diameter. The pore sizes in porous carbon activated by Na 2 CO 3 were 0.6 and 1.5 nm in diameter. These results indicated that pore structures could be controlled by chemical agents on the activation. The hydrogen storage ability of the porous carbon material activated by NaOH was the same as that activated by Na 2 CO 3 and the value was about 0.5 wt.% at 298 K. With a decrease in temperature, hydrogen storage ability was increased, and the difference of the maximum amount of stored hydrogen on these two porous carbon materials was made larger. The hydrogen storage ability at 77 K porous carbons activated by NaOH and Na 2 CO 3 indicated 3.7 and that for Na 2 CO 3 was 2.1 wt.%. From pore size distributions and temperature dependence, it was suggested that the size of pore for the hydrogen storage changed from 0.6 nm to both 0.6 and 1.1 nm with decreasing temperature.

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“…A comprehensive research of the adsorption capacity of carbon structures that were obtained by different research centers has been done in the paper [22]. It has been shown that the amount of adsorbed hydrogen depends directly on the pore surface area (Fig.…”

Section: Nanoporous Carbon Structuresmentioning

confidence: 99%