Mg–Ni–La based small hydrogen storage tank: kinetics, reversibility and reaction mechanisms

The improvement of de/rehydrogenation kinetics and reversibility of a Mg–Ni–La based small hydrogen storage tank by doping with TiF(4) and MWCNTs is reported for the first time. During sample preparation, MgH(2) milled with 20 wt% LaNi(5) and 5 wt% TiF(4) and MWCNTs produces Mg(2)NiH(4) and LaH(3). Two-step dehydrogenation of Mg(2)NiH(4) and MgH(2) is detected at 295 and 350 °C, respectively. Hydrogen desorption and absorption of the tank complete within 150 and 16 min, respectively, together with reversible hydrogen storage capacity up to 4.00 wt% H(2) (68% of theoretical value) upon 16 de/rehydrogenation cycles. Heat release from exothermic hydrogenation is removed effectively at the end of a double tube heat exchanger, where the reaction heat and heat transfer fluid are first in contact. Co-catalytic effects of Mg(2)NiH(4) and LaH(3) as well as good hydrogen diffusion benefit dehydrogenation kinetics and reversibility of the tank.