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Free keywords:
Hydrogen storage; Transition metal alanate; Dehydrogenation; Mechanical milling
Abstract:
The facile synthesis of ytterbium tetrahydroaluminate Yb(AlH4)3 is conducted by a mechanochemical procedure under hydrogen atmosphere for the first time. Results show that the synthesized Yb(AlH4)3 remains as an amorphous state. The thermal decomposition of Yb(AlH4)3 goes through a four-stage pathway with several amorphous intermediate phases during the process. The first dehydrogenation step of Yb(AlH)3 presents a relatively low apparent activation energy of 99.6 kJ mol−1, and ninety percent of the hydrogen from this stage can be liberated within 20 min at 160 °C. Rehydrogenation tests above 160 °C and 14 MPa hydrogen pressure demonstrate the unsuccessful rehydrogenations of the first decomposition step due to the formation of a thermodynamically more stable compound YbHCl.
