新型储氢材料金属氨硼烷肼合物的合成、结构及放氢性能的研究

Hydrogen is considered as one of the pormising fuels in the future. However, development of efficient hydrogen storage materials on board is of significant importance to the implementation of hydrogen fuel cell technologies. Recently, tremendous efforts have been devoted to metal amidoboranes (MNH2BH3), which suffer from a few drawbacks, i.e., high kinetic barrier, unsatisfied hydrogen capacity and toxic byproducts.Additionally, the combination of Hδ+ and Hδ- is one of the driving force in the dehydrogention of amidoborane. However, the unbalanced Hδ+ and Hδ- in amidoborane makes the dehydrogention imcomplete. Therefore, in this project, hydrazine (NH2NH2) is employed as legend to coodinate with metal amidoboranes forming new complexes, which may have promissing hydrogen storage properities. On the one hand, the addition of hydrazine can improve the hydrogen capacity of amidoboranes, lower the dehydrogenation temperature, and depress byproduct during the dehydrogenation. On the other hand, the ratio between Hδ+ and Hδ- can be adjusted by hydrazine so that dehydrogenation properties of amidoboane can be optimized. Therefore, this project is great helpful to the knowledge on the synthesis and dehydrogenation of amidoborane hydrazinate, and will have important academic value and promissing application in the future.

氢气以其清洁高效被认为是未来理想的能源载体。而高效车载储氢材料的开发是氢能大规模应用的瓶颈之一。近年来，金属氨硼烷(MNH2BH3)是人们研究的热点材料之一，但是该材料又存在一定缺点，例如：放氢温度高于质子膜燃料电池操作温度、氢含量有待提高、放氢过程有副产物等。另外由于金属氨硼烷放氢的主要驱动力之一为正氢(Hδ+)与负氢(Hδ-)的结合，而金属氨硼烷中正氢与负氢数量不匹配使得该类材料放氢不彻底。因此，本项目拟利用肼（NH2NH2）作为配体与金属氨硼烷络合形成配位化合物,对金属氨硼烷进行改性，得到放氢性能优异的储氢材料。一方面，肼的加入可以提高体系的储氢量，降低金属氨硼烷放氢温度，抑制放氢副产物；另一方面，通过添加肼可调节金属氨硼烷中的正氢与负氢的配比，从而达到优化材料放氢性能。因此本项目对于深入认识金属氨硼烷配合物合成及放氢机制均有普遍指导意义，具有重要的学术价值和良好的应用前景。

金属氨硼烷(MNH2BH3)是人们研究的热点储氢材料之一，但是该材料又存在一定缺点，例如：放氢温度高于质子膜燃料电池操作温度、氢含量有待提高、放氢过程有副产物等。另外由于金属氨硼烷放氢的主要驱动力之一为正氢(Hδ+)与负氢(Hδ-)的结合，而金属氨硼烷中正氢与负氢数量不匹配使得该类材料放氢不彻底。因此，本项目利用了肼（NH2NH2）作为配体与金属氨硼烷络合形成配位化合物,对金属氨硼烷进行改性，调节材料中正氢(Hδ+)与负氢(Hδ-)比例，得到了性能优异的新型储氢材料。.通过研究，我们掌握了锂代氨硼烷-肼合物、钙代氨硼烷-肼合物的合成方法，并对材料进行了详细的表征；考察材料的放氢行为，发现了肼的加入对材料放氢的本质影响及材料的放氢机理。共合成新物种6种，解析新晶体结构3种，其中筛选出的4LiNH2BH3-N2H4材料可以在75℃下释放7.1wt%的氢气。同时对材料体系进行了进一步拓展，即考察了硼氢化钙-肼合物的合成及催化放氢机理。.一方面，肼的加入提高了体系的储氢量，降低金属氨硼烷放氢温度，抑制放氢副产物；另一方面，通过添加肼调节了金属氨硼烷中的正氢与负氢的配比，优化材料放氢性能。本项目对于深入认识金属氨硼烷配合物合成及放氢机制均有指导意义，具有重要的学术价值和良好的应用前景。