Hydrogen generation kinetics via hydrolysis of Mg2Ni and Mg2NiH4 powders

Abstract

In this work, we produce Mg2NiH4 powder after hydrogenation of Mg2Ni and employ them for hydrogen generation via hydrolysis reaction in different type of solutions. The analysis of Mg2NiH4 powder reveals surface changes after hydrogenation process which induces the occurrence of cracks and alterations of chemical bonds. The extremely intense hydrogen kinetics is observed using acidic solution, with hydrogen generation rate of approx. 600 ml g−1·min−1 in the first reaction minute. The activation energy for the hydrolysis of Mg2NiH4 is calculated to be 29.45 kJ mol−1. An ageing experiment, which includes Mg2NiH4 powder stored for two months, discloses almost identical hydrogen generation volume as as-received Mg2NiH4 powder. Furthermore, the hydrolysis reaction between Mg2NiH4 and acidic solution is applied for electricity production via PEM fuel cell, which shows the maximum voltage generation of 1.28 V for more than 400 s with the external resistance of 200 Ω.