Article ID | Journal | Published Year | Pages | File Type |
---|---|---|---|---|
1282987 | International Journal of Hydrogen Energy | 2010 | 6 Pages |
Abstract
In this paper, we reported that the prepared nickel coated carbon nanofibers (NiCNFs) by electroless plating method exhibited superior catalytic effect on hydrogen absorption/desorption of magnesium (Mg). It is demonstrated that the nanocomposites of MgH2/5Â wt.% NiCNFs prepared by ball milling could absorb hydrogen very fast at low temperatures, e.g. absorb â¼6.0Â wt.% hydrogen in 5 min at 473Â K and â¼5.0 wt.% hydrogen in 10 min even at a temperature as low as 423Â K. More importantly, the desorption of hydrogen was also significantly improved with additives of NiCNFs. Diffraction scanning calorimetry (DSC) measurement indicated that the peak desorption temperature decreased 50Â K and the on-set temperature for desorption decreased 123Â K. The composites also desorbed hydrogen fast, e.g. desorb 5.5Â wt.% hydrogen within 20Â min at 573Â K. It is suggested that the new phase of Mg2Ni, and the nano-sized dispersed distribution of Ni and carbon contributed to this significant improvement. Johnson-Mehl-Avrami (JMA) analysis illustrated that hydrogen diffusion is the rate-limiting step for hydrogen absorption/desorption.
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Authors
C.Z. Wu, X.D. Yao, H. Zhang,