Hydrogen Generation by Hydrolysis of MgH(2)-LiH Composite

As a most promising material for hydrogen generation by hydrolysis, magnesium hydride (MgH(2)) is also trapped by its yielded byproduct Mg(OH)(2) whose dense passivated layers prevent the further contact of intimal MgH(2) with water. In this work, LiH, as a destroyer, has been added to promote the hydrogen properties of MgH(2). The results demonstrate that even 3 wt % LiH was added into MgH(2)-G, the hydrogen generation yield can increase about 72% compared to the hydrogen generation yield of MgH(2)-G. The possible mechanism is that Mg(2+) from the hydrolysis of MgH(2) preferentially bound with OH(−) ions from the hydrolysis of LiH to form Mg(OH)(2) precipitation, which is dispersed in water rather than coated on the surface of MgH(2). Moreover, adding MgCl(2) into hydrolysis solution, using ball milling technology, and increasing the hydrolysis temperature can make the hydrolysis rate higher and reaction process more complete. It is noted that a too high weight ratio of LiH with too high of a hydrolysis temperature will make the reaction too violent to be safe in the experiment. We determinate the best experimental condition is that the LiH ratio added into MgH(2) is 3 wt %, the hydrolysis temperature is 60 °C, and the concentration of MgCl(2) hydrating solution is 1 M. MgH(2)-LiH composite hydrogen generation technology can meet the needs of various types of hydrogen supply and has broad application prospects.