Studies on the Hydrogen Storage of Magnesium Nanowires by Density Functional Theory
Studies on the Hydrogen Storage of Magnesium Nanowires by Density Functional Theory
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DOI：
10.1021/jp808385c
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发表时间：
2009-01
影响因子：
3.7
通讯作者：
Lanlan Li;Bo Peng;Weiqiang Ji;Jun Chen
中科院分区：
文献类型：
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作者：
Lanlan Li;Bo Peng;Weiqiang Ji;Jun Chen
在本文中，我们利用第一性原理密度泛函理论研究了尺寸对 MgH2 纳米线热力学稳定性的影响，以及尺寸对镁和 MgH2 纳米线能量稳定性和电子态的依赖性。研究发现，随着直径的减小，镁和 MgH2 纳米线都变得不太稳定。计算得出 A1_MgH2 (Φ0.68 nm)、A2_MgH2 (Φ0.85 nm) 和 A3_MgH2 (Φ1.24 nm) 纳米线的解吸焓分别为 -20.64、34.54 和 61.86 kJ/mol H2，这些纳米线源自 A1_Mg (Φ0.32 nm)、A2_Mg 纳米线。分别为 (φ0.71 nm) 和 A3_Mg (φ1.04 nm)。该结果表明，随着 Mg/MgH2 纳米线直径的减小，脱氢焓发生不稳定。特别是，A2_MgH2纳米线的解吸焓为34.54 kJ/mol H2，对应的接近环境解吸温度为264.25 K，这表明纳米晶化是实现镁基氢实际应用的好方法...
In this article, we have studied the size effects on the thermodynamic stability of MgH2 nanowires as well as the size dependencies on the energetic stability and electronic states of magnesium and MgH2 nanowires using first-principles density functional theory. It is found that both magnesium and MgH2 nanowires become less stable as the diameter decreases. The desorption enthalpies were calculated to be −20.64, 34.54, and 61.86 kJ/mol H2 for the nanowires of A1_MgH2 (ϕ0.68 nm), A2_MgH2 (ϕ0.85 nm), and A3_MgH2 (ϕ1.24 nm), which were derived from the nanowires of A1_Mg (ϕ0.32 nm), A2_Mg (ϕ0.71 nm), and A3_Mg (ϕ1.04 nm), respectively. This result shows that a destabilization occurs in the dehydrogenation enthalpy as the diameters of Mg/MgH2 nanowires are reduced. In particular, a desorption enthalpy of 34.54 kJ/mol H2 for A2_MgH2 nanowire corresponds to an ambient-close desorption temperature of 264.25 K, indicating that nanocrystallization is a good way to achieve practical application of Mg-based hydrogen...