Promoted hydrogen release from ammonia borane by mechanically milling with magnesium hydride: a new destabilizing approach
Promoted hydrogen release from ammonia borane by mechanically milling with magnesium hydride: a new destabilizing approach
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通过机械研磨氢化镁促进氨硼烷中的氢释放：一种新的去稳定方法
DOI：
10.1039/b820401b
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发表时间：
2009-01-01
影响因子：
3.3
通讯作者：
Wang, Ping
中科院分区：
文献类型：
--
作者：
Kang, Xiangdong;Ma, Laipeng;Wang, Ping
氨硼烷（NH（3）BH（3），AB）是一种有趣的分子晶体，具有极高的氢容量和中等的热稳定性。在本研究中，我们展示了一种简单但有效的方法，用于在中等温度下使AB不稳定以促进氢释放。研究发现，机械球磨氢化镁（MgH（2））可以显著提高AB的脱氢性能，无论是动力学还是热化学方面。对于机械研磨的AB/0.5MgH（2）材料，在100摄氏度左右的温度下，可以在4小时内从AB中释放出超过8wt%的氢，而不会产生不期望的挥发性副产物。此外，AB/0.5MgH（2）样品的脱氢反应的放热比纯AB的放热明显更少。原位X射线衍射结果表明，MgH（2）添加剂在球磨和随后的加热过程中很好地保持了其相稳定性。同时，拉曼光谱和原位（11）B NMR研究表明，MgH（2）添加剂对AB的化学键合状态和分解过程/产物有较大影响。结合相/结构分析结果表明，MgH（2）通过发展与AB的固相相互作用发挥作用。
Ammonia borane (NH(3)BH(3), AB) is an intriguing molecular crystal with an extremely high hydrogen capacity and moderate thermal stability. In the present study, we show a simple but effective approach for destabilizing AB for promoted hydrogen release at moderate temperatures. It is found that mechanically milling with magnesium hydride (MgH(2)) can dramatically improve the dehydrogenation properties of AB, on both the kinetic and thermochemical aspects. For the mechanically milled AB/0.5MgH(2) material, over 8 wt% hydrogen can be released from AB within 4 h at around 100 degrees C without undesired volatile by-products. Moreover, the dehydrogenation reaction of the AB/0.5MgH(2) sample becomes significantly less exothermic than that of neat AB. In situ X-ray diffraction results demonstrate that the MgH(2) additive well maintains its phase stability during the ball-milling and the subsequent heating processes. Meanwhile, Raman spectroscopy and in situ (11)B NMR studies show that the MgH(2) additive exerts considerable influence on the chemical bonding state and decomposition process/products of AB. Combined phase/structure analyses results suggest that MgH(2) exerts effect via developing solid phase interaction with AB.