| Hydrogen generation via hydrolysis of nanocrystalline MgH2 and MgH2-based composites |
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| 作者姓名： | 胡连喜 王尔德 |
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| 作者单位： | School of Materials Science and Engineering, Harbin Institute of Technology, Harbin 150001, China |
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| 摘 要： | Nanocrystalline MgH2 and MgH2-based composites with 25% （mass fraction） of Al, Ca, or CaH2 as an individual additive respectively were prepared by ball milling. The crystallite size and morphology of the as-milled powders were characterized and their hydrolysis behaviours were investigated in comparison with commercial polycrystalline MgH2. The results show that the crystallite size of both MgH2 and MgH2-based composites is reduced to less than 13 nm after milling for 15 h. Due to its enhanced specific surface area and unique nanocrystalline structure, the as-milled MgH2 shows much better hydrolysis kinetics than the commercial polycrystalline MgH2, with the hydrolysed fraction upon hydrolysing for 70 min enhances from 7.5% to about 25%. As compared with the as-milled MgH2, the MgH2-based composites with either Call2 or Ca as an additive present further greatly improved hydrolysis kinetics, with the hydrolysed fraction for 80 min achieving about 76% and 62% respectively. However, the addition of Al doesn＇t show any positive effect on the improvement of the hydrolysis kinetics of Mg H2.
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| 关 键 词： | 氢能 水解方法 微晶结构 MgH2 化学物 多晶结构 |
| 文章编号： | 1003-6326（2005）05-0965-06 |
| 收稿时间： | 2005-01-07 |
| 修稿时间： | 2005-05-04 |
Hydrogen generation via hydrolysis of nanocrystalline MgH2 and MgH2-based composites |
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| HU Lian-xi,WANG Er-de.Hydrogen generation via hydrolysis of nanocrystalline MgH2 and MgH2-based composites[J].Transactions of Nonferrous Metals Society of China,2005,15(5):965-970. |
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| Authors: | HU Lian-xi WANG Er-de |
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| Abstract: | Nanocrystalline MgH2 and MgH2-based composites with 25% (mass fraction) of Al, Ca, or CaH2 as an individual additive respectively were prepared by ball milling. The crystallite size and morphology of the as-milled powders were characterized and their hydrolysis behaviours were investigated in comparison with commercial polycrystalline MgH2. The results show that the crystallite size of both MgH2 and MgH2-based composites is reduced to less than 13 nm after milling for 15 h. Due to its enhanced specific surface area and unique nanocrystalline structure, the as-milled MgH2 shows much better hydrolysis kinetics than the commercial polycrystalline MgH2, with the hydrolysed fraction upon hydrolysing for 70 min enhances from 7.5% to about 25%. As compared with the as-milled MgH2, the MgH2-based composites with either CaH2 or Ca as an additive present further greatly improved hydrolysis kinetics, with the hydrolysed fraction for 80 min achieving about 76% and 62% respectively.However, the addition of Al doesn't show any positive effect on the improvement of the hydrolysis kinetics of MgH2. |
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| Keywords: | ball milling nanostructured material MgH2 chemical hydride hydrogen generation by hydrolysis |
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