Synthesis and hydrogen absorption/desorption properties of Mg-Nb2O5-SWCNT/MWCNT nanocomposite prepared by reactive milling
Synthesis and hydrogen absorption/desorption properties of Mg-Nb2O5-SWCNT/MWCNT nanocomposite prepared by reactive milling
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DOI：
10.1016/j.jallcom.2015.10.042
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发表时间：
2016-01-25
影响因子：
6.2
通讯作者：
Hwang, Sheng-Jye
中科院分区：
文献类型：
--
作者：
Chuang, Yu-Siang;Hwang, Sheng-Jye
在氢气反应气氛（P = 3.0 MPa）中球磨不同时间制备了Mg-Nb 2 O 5-SWCNT和Mg-Nb 2 O 5-MWCNT复合材料，系统研究了其吸附行为和微观结构。结果表明，球磨1 h后的Mg-Nb 2 O 5-MWCNT和Mg-Nb 2 O 5-MWCNT的吸放氢动力学得到明显改善。在573 K时，这两种复合材料在3.0 MPa的初始氢气压力下吸氢量为5.81- 4.88wt%，在600 s内放氢量为5.14- 4.01wt%。此外，球磨1h后的复合材料在298 ~ 573 K的温度范围内也具有一定的吸氢能力。然而，Mg-Nb 2 O 5-SWCNT 1小时研磨样品具有比Mg-Nb 2 O 5-MWCNT 1小时研磨样品更好的氢化/脱氢动力学。由Kissinger曲线估算出Mg-Nb 2 O 5-SWCNT球磨1 h后的吸氢和放氢表观活化能分别为12.84 kJ/mol和102.69 kJ/mol。这些数字低于具有相同研磨时间的纯Mg样品，其分别高3.14和2.0倍。Mg-Nb 2 O 5-SWCNT球磨1 h后的脱附温度和脱氢焓分别为140 K和20.72 kJ/mol，低于纯Mg/MgH 2。(C)2015 Elsevier B. V.版权所有。
Mg-Nb2O5-SWCNT and Mg-Nb2O5-MWCNT composites were prepared by ball-milling in a hydrogen reactive atmosphere (P = 3.0 MPa) for different periods of time, and their sorption behaviors and microstructure were investigated systematically. The results showed that the hydriding and dehydriding kinetics of Mg-Nb2O5-SWCNT and Mg-Nb2O5-MWCNT 1 h milled samples were markedly improved. At 573 K, these two composites could absorb 5.81-4.88 wt% hydrogen under initial hydrogen pressure of 3.0 MPa, and desorb 5.14-4.01 wt% hydrogen within 600 s. Furthermore, these 1 h milled composites could also absorb hydrogen in a moderate temperature range between 298 K and 573 K. However, the Mg-Nb2O5-SWCNT 1 h milled sample had better hydriding/dehydriding kinetics than the Mg-Nb2O5-MWCNT 1 h milled sample. The apparent activation energies for the hydrogen absorption and desorption of the Mg-Nb2O5-SWCNT 1 h milled sample were estimated to be 12.84 kJ/mol and 102.69 kJ/mol from the Kissinger's plot. These figures were lower than those of a pure Mg sample with the same milling time, which were 3.14 and 2.0 times higher, respectively. The desorption temperature and the dehydrogenation enthalpy of the Mg-Nb2O5-SWCNT 1 h milled sample were 140 K and 20.72 kJ/mol, respectively, which were lower than those of pure Mg/MgH2. (C) 2015 Elsevier B.V. All rights reserved.