Dehydrogenation characteristics of LiAlH4 improved by in-situ formed catalysts

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 degrees C, which is 64 degrees 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 degrees C. At lower temperatures of 110 degrees C and 80 degrees 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 kJ/mol, which is 67 kJ/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. (C) 2016 Science Press and Dalian Institute of Chemical Physics, Chinese Academy of Sciences. Published by Elsevier B.V. and Science Press. All rights reserved.