In situ synchrotron X-ray diffraction study on the improved dehydrogenation performance of NaAlH4-Mg(AlH4)2 mixture

The dehydrogenation performance and mechanism of the synthesized NaAlH4-Mg(AlH4)(2) powders were investigated by performing thermogravimetric analysis and in situ synchrotron X-ray diffraction analysis. NaAlH4 not only facilitates the first step dehydrogenation of Mg(AlH4)(2) in lowering its initial dehydrogenation temperature but also increases the total amount of H-2 released. Besides, MgH2 and/or Al phases, the products of the first step dehydrogenation reaction, play a catalytic role in lowering the initial dehydrogenation temperature of NaAlH4. The synthesized NaAlH4-Mg(AlH4)(2) mixture has an initial dehydrogenation temperature as low as 120 degrees C, and is able to release 5.35 wt% H-2 below 350 degrees C. The self-catalytic dehydrogenation behavior of the NaAlH4-Mg(AlH4)(2) mixture was elaborated in this work with the aid of in situ synchrotron XRD. (c) 2013 Elsevier B.V. All rights reserved.