The hydrogen storage properties and catalytic mechanism of FeCl2-doped LiAlH4 were investigated in minute details. LiAlH4-2 mol% FeCl2 samples start to release hydrogen at 76 °C, which is 64 °C lower than that of as-received LiAlH4. Isothermal desorption measurements show that the 2 mol% FeCl2-doped sample releases 7.0 wt% of hydrogen within 17 min at 250 °C. At lower temperatures of 110 °C and 80 °C, the sample can release 4.4 wt% and 3 wt% of hydrogen, respectively. The apparent activation energy of LiAlH4-2 mol% FeCl2 samples for R2 is 105.02 k J/mol, which is 67 k J/mol lower than that of pure LiAlH4. The reaction between LiAlH4 and FeCl2 during ball milling was found by analyzing the X-ray diffraction results,and Fe-Al particles formed in-situ from the reaction act as the real catalyst for the dehydrogenation of LiAlH4.
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Institute of New Energy Material Chemistry, Collaborative Innovation Center of Chemical Science and Engineering (Tianjin), Key Laboratory of Advanced Energy Materials Chemistry (MOE), Tianjin Key Lab of Metal, Nankai University;