Mechanochemical transformations in NaNH2-MgH2 mixtures

作者：Singh Niraj K; Kobayashi Takeshi; Dolotko Oleksandr; Wiench Jerzy W; Pruski Marek^*; Pecharsky Vitalij K

来源：Journal of Alloys and Compounds, 2012, 513: 324-327.

DOI：10.1016/j.jallcom.2011.10.041

• Hydrogen storage
• Mechanochemical transformation
• Solid-state NMR
• X-ray diffraction

Mechanochemical transformations occurring during ball milling of sodium amide (NaNH2) with magnesium hydride (MgH2) taken in 2:3 and 2:1 molar ratios have been investigated using X-ray powder diffraction (XRD) and solid-state nuclear magnetic resonance (SSNMR) techniques. For the 2NaNH(2)-3MgH(2) system the mechanochemical reaction proceeds via the formation of MgNH as an intermediate, whereas magnesium nitride (Mg3N2), sodium hydride (NaH) and hydrogen (similar to 5 wt%) form as the final products. The overall solid state reaction for this system is 2NaNH(2) + 3MgH(2) -%26gt; Mg3N2 + 2NaH + 4H(2). However, the mechanochemical transformation of the 2NaNH(2)-MgH2 system proceeds through the reaction: 2NaNH(2) + MgH2 -%26gt; Mg(NH2)(2) + 2NaH, without any hydrogen release. Comparison of the mechanochemical transformations with the previously studied thermochemical transformations reveals that the two approaches lead to the same final products via different reaction pathways.

• 出版日期2012-2-5