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In this work, we investigated the effects of BaFe 12 O 19 on the dehydrogenation properties of LiAlH 4. It was shown that the LiAlH 4 doped with 10 wt% of BaFe 12 O 19 had started to release hydrogen at 95 °C, as compared with undoped LiAlH 4 (more than 140 °C). Desorption kinetic result showed that the BaFe 12 O 19 -doped LiAlH 4 sample can release more hydrogen (4.2 wt% of H 2) compared to undoped LiAlH 4 (less than 1.0 wt%) at 90 °C for 2.5 h. Results of differential scanning calorimetry measurements showed that the thermal events had remained the same for the BaFe 12 O 19 –doped LiAlH 4 sample and the undoped LiAlH 4. However, thermal events occurred at a lower temperature after the addition of 10 wt% BaFe 12 O 19. The desorption activation energies of the first two reactions for the BaFe 12 O 19 –doped LiAlH 4 sample were decreased by about 32 kJ/mol and 22 kJ/mol, compared to undoped LiAlH 4 , respectively. Scanning electron microscopy images revealed the size of particles became smaller with the addition of BaFe 12 O 19. It is believed that the improvements in the desorption process were catalysed by the Fe, LiFeO 2 and amorphous Ba or Ba-containing that were formed in situ during the dehydrogenation process. • BaFe 12 O 19 showed superior catalytic effects for LiAlH 4. • BaFe 12 O 19 -doped LiAlH 4 could desorb 4.2 wt% H 2 within 2.5 h at 90 °C. • The new species of Fe, LiFeO 2 and Ba-containing play a synergistic catalytic role. [ABSTRACT FROM AUTHOR]

The influences of MgNiO 2 nanoflakes that are synthesised via a simple hydrothermal method on the hydrogen sorption performance of MgH 2 are studied for the first time. The temperature-programmed desorption curve shows that when 10 wt% of MgNiO 2 is added to MgH 2 , hydrogen has started to release at 258 °C in comparison to the milled MgH 2 , which has released at 340 °C. The absorption kinetics for the MgNiO 2 -doped MgH 2 sample demonstrates great hydrogen absorption with the capacity of hydrogen is up to 6.1 wt% within 10 min at 200 °C, while the milled MgH 2 has only absorbed about 4.4 wt%. In terms of desorption kinetics, the MgNiO 2 -doped MgH 2 sample has shown faster desorption with 5.1 wt% of hydrogen is released in a duration of 10 min while the milled MgH 2 has only released about 0.6 wt% of hydrogen. The Arrhenius plot shows that doping MgH 2 with MgNiO 2 has lowered the activation energy to 108.0 kJ mol−1, a decrease of 52.0 kJ mol−1 in comparison to the as-milled MgH 2 (160.0 kJ mol−1). It is believed that the formations of new compounds, MgO and NiO, act as active species and offer significant synergetic catalytic effect, thus improving the hydrogen storage performance of MgH 2. • MgNiO 2 nanoflakes are prepared via a simple hydrothermal method. • MgNiO 2 nanoflakes showed superior catalytic effects for MgH 2. • MgNiO 2 -doped MgH 2 could desorb 5.1 wt% H 2 within 10 min at 320 °C. • MgNiO 2 -doped MgH 2 could absorb 6.1 wt% H 2 within 10 min at 200 °C. • The new species of MgO and NiO play a synergistic catalytic role. [ABSTRACT FROM AUTHOR]