Metal-Hydrogen Complex Compounds as Hydrogen Storage Materials

摘要

A new production process of sodium borohydride (NaBH4) as a hydrogen storage material was developed by using sodium metaborate (NaBCh) in which a simple reaction given as NaBO_2 + 2Mg + 2H_2 ->NaBH_4 + 2MgO took place at considerably high reaction rate by changing the system temperature dynamically. The process applies the transitional states of hydrogen at the extreme surface of Mg when it is hydrogenated and dehydrogenated by the constant rate of temperature change, dT/dt (deg C/s). The rate of conversion is found significantly dependent on dT/dt and regulated by the oxidation level of Mg particles. Roles of protide (anionic hydrogen; H~-) in Mg centre dot (2H~-) under transitional conditions, Mg + H_2 ->MgH_2 ->Mg centre dot (2H~-), will be discussed with regard to the exchange reaction between NaBO_2 and NaBH_4.