In Situ High-Resolution Observation for Decomposition of NaAlH4


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NaAlH4 has a theoretical hydrogen capacity of 5.6 wt. % with two-step reaction, and the control of the reaction temperature and reversibility is a critical issue for onboard application. To clarify nano-structural details of decomposition of NaAlH4, the in-situ annealing experiment was carried out in a high resolution microscope. It was confirmed that NaAlH4 decomposed at between 200 and 300°C, resulted in formation of many gas bubbles at interface between the particle and oxide film. A reactive intermediate, Na3AlH6, may decompose in this temperature range. Sodium alanate particle was originally agglomeration of small nano-sized crystal with the size of 10 – 20 nm, and the crystal grain grew to 110 nm in diameter after completing decomposition at around 400°C. This is the first step for examination of the microstructural response of catalysts on hydrogen storage materials.



Materials Science Forum (Volumes 561-565)

Main Theme:

Edited by:

Young Won Chang, Nack J. Kim and Chong Soo Lee




H. Kawasaki et al., "In Situ High-Resolution Observation for Decomposition of NaAlH4", Materials Science Forum, Vols. 561-565, pp. 1621-1624, 2007

Online since:

October 2007




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