Basic research on regeneration method of metal amidoboranes

2019 Fiscal Year Final Research Report

• Project/Area Number: 17K00627
• Research Category: Grant-in-Aid for Scientific Research (C)
• Allocation Type: Multi-year Fund
• Section: 一般
• Research Field: Environmental conscious materials and recycle
• Research Institution: Hiroshima University
• Principal Investigator: Kojima Yoshitsugu 広島大学, 自然科学研究支援開発センター, 教授 (20394546)
• Co-Investigator(Kenkyū-buntansha): 中川 鉄水 琉球大学, 理学部, 助教 (50647261)
• Project Period (FY): 2017-04-01 – 2020-03-31
• Keywords: 水素貯蔵材料 / アンモニアボラン / 再水素化 / 水素化リチウム / 金属アミドボラン / アンモニア / ヒドラジン

Outline of Final Research Achievements

Lithium amidoborane (LiAB), which was synthesized by reacting lithium hydride (LiH) with ammonia borane (AB), was dehydrogenated by heating to obtain several conditions of spent fuels. These 1-2 eq.H2 dehydrogenated products were reacted with hydrazine and ammonia in order to obtain the intermediates of regeneration. As a result of investigating reacted products by using 11B-NMR measurement, X-ray diffraction (XRD) and infrared spectroscopy, BH3 species are observed after both soaking liquid NH3 and hydrazine. This result stands for that the similar reaction route with regeneration of AB proceeds in the case of LiAB. On the other hand, KAB (KNH2BH3) and CaAB (Ca(NH2BH3)2) also recovered BH3 bonds although their regeneration was incomplete. Hence, regeneration of KAB and CaAB is possible but more investigation to find proper regeneration condition is required.

Free Research Field

水素貯蔵材料

Academic Significance and Societal Importance of the Research Achievements

金属アミドボラン（MAB）は水素貯蔵量が多いことから水素貯蔵材料として期待されている。しかしながら、再生メカニズムが不明な問題がある。本研究ではリチウムアミドボラン（LiAB）から水素放出後に生成する副生成物の水素再充填（再生）メカニズム解明に成功した。更に金属アミドボランのうちカリウムアミドボラン（KAB）とカルシウムアミドボラン（CaAB）の単相合成に成功し、これらが再生可能であるという証拠を突き止めた。上記の成果は再生反応の法則性を理解する手がかりとなり、本研究で用いた再生法がアミドボラン系にも汎用的な手法であることの証明にもなった。