Catalytic effect of SrFe12O19 on the hydrogen storage properties of LiAlH4

Abstract

The effects of a SrFe12O19 addition on the hydrogen storage properties of LiAlH4 were investigated for the first time, to the best of our knowledge. The addition of the SrFe12O19 show improved dehydrogenation performance compared with that of undoped LiAlH4. In fact, the onset desorption temperatures decreased from 140 °C to 80 °C in the first reaction stage and from 180 °C to 135 °C in the second reaction stage. In terms of the dehydrogenation kinetics, the 10 wt% SrFe12O19-added LiAlH4 sample released approximately 5.54 wt% hydrogen at 130 °C after 20 min desorption, whereas the as-milled LiAlH4 sample released less than 0.3 wt% hydrogen in the same period of time and temperature. Kissinger analysis indicates that the apparent activation energies of the first two dehydrogenation reactions of LiAlH4 are decreased by approximately 27 and 15 kJ/mol, respectively, after the addition of SrFe12O19. It is reasonable to conclude that the formation of an in situ active species of Fe and LiFeO2 and amorphous Sr or Sr-containing phases could play a catalytic role in enhancing the dehydrogenation performance of LiAlH4.