Hydrogenation of nanostructured graphite by mechanical grinding under hydrogen atmosphere

Kiyobayashi, Tetsu; Komiyama, Keita; Takeichi, Nobuhiko; Tanaka, Hideaki; Senoh, Hiroshi; Takeshita, Hideki; Kuriyama, Nobuhiro

doi:10.1016/j.mseb.2003.10.093

Cited by 20 publications

(11 citation statements)

References 19 publications

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“…However, the temperatures of greater than 900 C are required to desorb an appreciable amount of hydrogen [2][3][4][5][6]. Subsequently, it was reported that the milling conditions-such as the milling duration and the type of milling media usedcould affect the structure of the resulting milled graphite materials and their hydrogen storage properties (including the ratio of evolved hydrocarbon gases to hydrogen) [7][8][9][10][11][12][13][14][15][16][17]. The poor reversibility of hydrogenated ball-milled graphite is a major barrier to its potential use as a hydrogen storage medium.…”

Section: Introductionmentioning

confidence: 99%

Hydrogen storage properties of ball-milled graphite with 0.5 wt% Fe

Zhang

Book

2011

Int. J. Energy Res.

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SUMMARY Ball‐milled hydrogenated graphite‐iron materials have attracted interest as possible hydrogen storage media because of theoretically estimated hydrogen capacities of about 10 wt%. However, such a value needs to be experimentally verified. In this work, graphite‐0.5 wt% Fe was milled under 3 bar hydrogen in a tungsten carbide milling pot. The effect of iron on the microstructure and hydrogen storage properties of milled graphite was investigated by thermal gravimetric analysis–mass spectrometry, X‐ray diffraction, and transmission electron microscopy. When a 10‐hour milled graphite with 0.5 wt% Fe sample was heated under argon to 990 °C, 9.6 wt% of hydrogen was released, which is almost double than that for a graphite sample with no iron (5.5 wt% hydrogen). The addition of iron also was found to reduce the onset temperature of hydrogen desorption by 50 to 350 °C. However, for a longer milling time of 40 hours, the amount of hydrogen desorbed for graphite‐0.5 wt% Fe decreased, and methane also was detected. The results suggest that iron carbide produced during milling plays a catalytic role, increasing the hydrogen storage capacity and lowering the onset temperature of hydrogen desorption. Copyright © 2011 John Wiley & Sons, Ltd.

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Section: Introductionmentioning

confidence: 99%

Hydrogen storage properties of ball-milled graphite with 0.5 wt% Fe

Zhang

Book

2011

Int. J. Energy Res.

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“…So far, the hydrogen absorption and desorption properties on C nano H x have been investigated by various experimental methods, thermal analysis and structural examination [2][3][4][5][6][7], neutron scattering measurements [8,9], infra-red absorption spectroscopy [10], nuclear magnetic resonance spectroscopy [11,12], electron energy-loss spectroscopy with transmission electron microscope [13][14][15], and electron spin resonance spectroscopy [16].…”

Section: Introductionmentioning

confidence: 99%

Anomalous hydrogen absorption on non-stoichiometric iron-carbon compound

Miyaoka

Ichikawa

Fujii

et al. 2010

Journal of Alloys and Compounds

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a b s t r a c tOn the synthesis of nano-structural hydrogenated graphite by ball-milling under H 2 atmosphere, iron contamination was mingled from steel balls during ball-milling. It is clarified by spectroscopic measurements that the mingled iron formed a non-stoichiometric iron-carbon (Fe-C) compound. The Fe-C phase was transformed to a well-ordered phase with H 2 desorption at 450 • C, suggesting that the hydrogen atoms were anomalously trapped at the Fe-C phase. With respect to hydrogen absorbing properties, the mingled iron enhanced the hydrogen capacity by about 50% compared with iron free hydrogenated graphite, where H/Fe was about 13 mass%. Therefore, if the hydrogen absorption site originated in the Fe-C phase could be synthesized independently, it should be recognized as a promising hydrogen storage system.

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“…The hydrogenated nanostructured graphite is hereafter abbreviated as HNG. Three parts of the HNG sample powder were heat-treated in a vacuum vessel at a heating rate of 10 K/min, following the previous TDS experiment [12], and cooled when the sample temperature reached 650 K, 800 K and 1000 K, respectively. The selected temperatures correspond to, respectively, the end of the first broad peak, start of the sharp high-temperature peak and end of the sharp peak in the TDS.…”

Section: Methodsmentioning

confidence: 99%