Catalysis of Lithium Chloride and Alkali Metal Borohydrides on Hydrogen Generation of Ammonia and Lithium Hydride System

The catalytic properties of titanium (Ti), titanium hydride (TiH2), and ammonia (NH3) absorbing materials, which are lithium chloride (LiCl), lithium borohydride (LiBH4), and sodium borohydride (NaBH4), are investigated to improve the kinetic properties of the hydrogen storage system composed of NH3 and lithium hydride (LiH). The NH3 absorbing materials reveal a significant catalytic effect on the hydrogen generation reaction, although Ti is expected as the catalyst. NaBH4 is the most effective catalyst among them, and then the reaction yield reaches to more than 90% for 12 h, although the yield in the case of LiH without catalysts is less than 50% for 12 h. Furthermore, the catalysis is strongly related to the NH3 absorption properties of the catalysts. As the catalytic mechanism, it can be proposed that the NH3 condensation state is realized in the catalysts and improves the kinetic properties, such as the frequency factor.