Composite Materials based on Light Elements for Hydrogen Storage
Composite Materials based on Light Elements for Hydrogen Storage
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DOI：
10.2320/matertrans.46.1
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发表时间：
2005-01
影响因子：
1.2
通讯作者：
T. Ichikawa;Nobuko Hanada;S. Isobe;H. Leng;H. Fujii
中科院分区：
文献类型：
--
作者：
T. Ichikawa;Nobuko Hanada;S. Isobe;H. Leng;H. Fujii
本文综述了近年来轻元素Li、C和Mg基纳米复合储氢材料的研究结果。结果表明：在Li-N-H体系中，如球磨后的氨化锂和氢化锂的混合物中加入少量TiCl 3（1mol%），在150 ~ 250 ℃范围内有大量的氢（~ 6 mass%）发生吸放，且可逆性好，反应速率高。此外，在球磨的3 Mg（NH 2）2和8LiH的混合物中，在140至220 ℃的温度下可逆地储存了-7%质量的氢，指示了合适的储氢材料之一。在含有少量纳米级Fe（~ 2at.%）的石墨中，在低于1 MPa的H2-气压下球磨80 h，大量的氢（~ 7质量%）被化学吸附。球磨80 h后，石墨的化学吸附氢容量随球磨压力的增加而降低（在6 MPa时降至~ 4：1质量%），而石墨的物理吸附氢容量随球磨压力的增加而增加，在6 MPa时达到0：5 ~ 1：0质量%。不幸的是，化学吸附氢的脱附温度高于300 ℃。因此，作为储氢系统之一的碳基材料的发展需要取得一些突破。另一方面，由Ni纳米颗粒或Nb氧化物催化的纳米复合Mg显示出上级可逆储氢性能：在150 ~ 250 ℃温度范围内可逆储氢量为6：5（质量%）。特别是Nb_2 O_5还原生成的MgH_2催化剂，其表面的Nb金属以纳米尺度均匀分散，是迄今为止我们研究的最好的催化剂。因此，一些d-电子过渡金属纳米颗粒催化的镁纳米复合材料似乎是可以接受的实际应用。
In this paper, we review our recent experimental results on hydrogen storage properties of light elements Li, C and Mg based nanocomposite materials. The results are summarized as follows: In the Li-N-H system, such as the ball milled 1:1 mixture of Li amide and Li hydride containing a small amount of TiCl3 (1 mol%), a large amount of hydrogen (� 6 mass%) is absorbed and desorbed in the temperature range from 150 to 250 � C with good reversibility and high reaction rate. Furthermore, in the ball milled mixture of 3Mg(NH2)2 and 8LiH, � 7 mass% of hydrogen is reversibly stored in the temperature from 140 to 220 � C, indicating one of the suitable hydrogen storage materials. In graphite containing a small amount of nanometer sized Fe (� 2 at.%), a large amount of hydrogen (� 7 mass%) is chemisorbed by ball milling for 80 h under less than 1 MPa of H2-gas pressure. However, the chemisorbed hydrogen capacity decreases with increase in the milling pressure for the 80 h ball milled graphite (down to � 4:1 mass% at 6 MPa), while the physisorbed hydrogen capacity in graphite increases with increase in the milling pressure, reaching up to 0:5� 1:0 mass% at 6 MPa. Unfortunately, the desorption temperature of chemisorbed hydrogen is higher than 300 � C. Therefore, some break-through is necessary for the development of carbon-based materials as one of the hydrogen storage systems. On the other hand, some nano-composite Mg catalyzed by Ni nano-particle or Nb oxide reveals superior reversible hydrogen storage properties: � 6:5 mass% of hydrogen is reversibly stored in the temperature range from 150 to 250 � C. Especially, the Nb metals uniformly dispersed in nanometer scale on the surface of MgH2, which was produced by reduction of Nb2O5, is the best catalyst we have studied so far. Thus, it seems that some Mg nano-composites catalyzed by nano-particles of d-electron transition metals is acceptable for practical applications.