LAUSR

Abstract The effect of the K2ZrF6 catalyst on the hydrogen storage properties of the 4MgH2-LiAlH4 composite was studied for the first time. The onset dehydrogenation temperature of the 4MgH2-LiAlH4-K2ZrF6 composite was reduced to approximately 95 °C and 250 °C for the first two dehydrogenation stages; these values were lower by 40 °C and 25 °C compared with the undoped composite. Desorption kinetics measurement revealed that K2ZrF6-doped 4MgH2-LiAlH4 released 3.0 wt% hydrogen in 20 min, whereas the undoped composite only released 2.0 wt% hydrogen within the same time. The activation energy for MgH2-relevant decomposition in the 4MgH2-LiAlH4 composite was reduced from 129.8 kJ/mol to 102.9 kJ/mol after the addition of the K2ZrF6 catalyst. The X-ray diffraction spectra displayed the formation of novel peaks of KH, Al3Zr and LiF after the de/rehydrogenation processes. These species functioned as active species and played a catalytic role in enhancing the dehydrogenation properties of the Mg-Li-Al composite.