Enhancement of the hydrogen release of Mg(BH4)2 by concomitant effects of nano-confinement and catalysis

Abstract Magnesium borohydride, Mg(BH 4 ) 2 , is an interesting material for hydrogen storage due to its high hydrogen content (14.9 wt.% of H 2 ). Unfortunately, a temperature of at least 350 °C is needed for releasing its hydrogen and the rehydrogenation process is only feasible under harsh conditions (950 bar H 2 and 300 °C). In order to improve the performances of this compound, we analyze in this study the concomitant effects of nano-confinement into mesoporous carbons and addition of Ni Pt catalysts. This study uses different characterization tools to determine the effects of both nano-confinement and catalysts onto the pathway of decomposition. Usually, bulk Mg(BH 4 ) 2 decomposes in several steps passing through intermediate species for which activation energies are high. In this study, we show that the confinement and catalyst addition on Mg(BH 4 ) 2 result in a single step of hydrogen release and an activation energy below that of the bulk material with a value of 178 ± 14 kJ mol −1 as determined by the Kissinger's method. Interestingly, the hydrogen release is fully completed, i.e. 8H atoms per Mg(BH 4 ) 2 formula unit are released, in less than 2 h at 350 °C.