Compressed hydrogen production via reaction between liquid ammonia and alkali metal hydride

Abstract

Ammonia NH 3 is recognized as one of the attractive hydrogen H 2 carriers because it has a high hydrogen content of 18 mass% and it is easily liquefied under about 1 MPa of pressure at a room temperature. NH 3 can react with alkali metal hydrides and generate H 2 even at room temperature, resulting that metal amides are formed as reaction products. The H 2 generation is exothermic reaction, and it is not effectively prevented by H 2 partial pressure in a closed system as thermodynamic properties. In this work, we demonstrated the production of compressed H 2 by the reaction between liquid NH 3 and lithium hydride LiH in a closed pressure vessel, where liquid NH 3 would realize better kinetic properties for the reaction with metal hydride than gaseous NH 3. Actually, more than 12 MPa H 2 was obtained within several hours.