Improved dehydrogenation properties of Mg(BH4)2·2NH3 combined with LiAlH4.

The decomposition properties of Mg(BH 4 ) 2 ·2NH 3 combined with LiAlH 4 mixtures were investigated systematically. It revealed that the hydrogen desorption temperature shifted to 100 °C with the superior suppression of ammonia, and desorption rates were improved with the increased LiAlH 4 ratio (0.5, 1, 2), respectively. When the LiAlH 4 ratio was increased to 2, the binary system exhibited three dehydrogen steps with an onset temperature at 98 °C and 5.4 wt % H 2 desorbed rapidly at the same temperature, while no apparent evolution of H 2 was observed for individual Mg(BH 4 ) 2 ·2NH 3 and LiAlH 4 below 150 °C. The dehydrogenation rate of the system was improved by about 92% more than that of Mg(BH 4 ) 2 ·2NH 3 . These results indicate that the dehydrogenation of Mg(BH 4 ) 2 ·2NH 3 is enhanced significantly by the introduction of LiAlH 4 . The synergetic factor of the aided-cation effect and dihydrogen interaction may contribute to prevent the NH 3 group from being dissociated as ammonia. [ABSTRACT FROM AUTHOR]