Hydrogen generation by CaH 2-induced hydrolysis of Mg 17Al 12 hydride
Abstract
The Mg 17Al 12 intermetallic compound is brittle and easily pulverized and hydrogenated, which holds the promise as a hydrogen source because the theoretical hydrogen generation capacity by hydrolysis of Mg 17Al 12 hydride (MHA) is as high as 13.6 wt.%. However, it was found that the hydrolysis reaction of MHA without any additives would be rapidly interrupted because of the formation of a passive layer on the surface of the particles. The influence of CaH 2 on the hydrogen generation performances of the MHA + CaH 2 mixtures by hydrolysis was investigated in this paper. The result showed that the addition of CaH 2 by ball-milling is effective to improve the hydrolysis reactivity of the mixtures. The best was obtained by MHA+10wt.% CaH 2 mixture ball-milled for 1 h, which produces 1389 ml H 2/g at 70 °C after 1 h of hydrolysis in pure water, namely the hydrogen generation yield reaches 94.8%. In this paper, the reasons of the improvement and the reaction mechanism have also been discussed respectively.
- Publication:
-
International Journal of Hydrogen Energy
- Pub Date:
- January 2011
- DOI:
- 10.1016/j.ijhydene.2011.09.022
- Bibcode:
- 2011IJHE...3615698X
- Keywords:
-
- Hydrogen generation;
- Hydrolysis;
- Mg <SUB loc="post">17</SUB>Al <SUB loc="post">12</SUB> hydride;
- CaH <SUB loc="post">2</SUB>