Discovery of A New Al Species in Hydrogen Reactions of NaAlH4

作者：Ivancic Timothy M^*; Hwang Son Jong; Bowman Robert C Jr; Birkmire Derek S; Jensen Craig M; Udovic Terrence J; Conradi Mark S

来源：Journal of Physical Chemistry Letters, 2010, 1(15): 2412-2416.

DOI：10.1021/jz1007998

The NaAlH4 system remains the archetype of hydrogen storage solids. However, the detailed mechanisms of the hydrogen reactions of NaAIH(4) remain unknown. We report Al-27 in situ nuclear magnetic resonance (NMR) spectroscopic data revealing an Al-bearing mobile species that could provide the large scale metal-atom transport needed for rehydriding. This new species forms under reaction conditions but can be captured at ambient temperature using excess H-2 pressure. The NMR measurements demonstrate that the species is highly mobile (at 20 degrees C) and carries both Al and H atoms. On the basis of the Al-27 shift (close to NaAlH4) and the disorder evident in X-ray diffraction the species is identified as highly defective NaAlH4, likely having a large AIH(3) vacancy concentration.

• 出版日期2010-8-5