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Metal‐Borohydride‐Modified Zr(BH 4 ) 4 ⋅8 NH 3 : Low‐Temperature Dehydrogenation Yielding Highly Pure Hydrogen
Author(s) -
Huang Jianmei,
Ouyang Liuzhang,
Gu Qinfen,
Yu Xuebin,
Zhu Min
Publication year - 2015
Publication title -
chemistry – a european journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.687
H-Index - 242
eISSN - 1521-3765
pISSN - 0947-6539
DOI - 10.1002/chem.201501461
Subject(s) - dehydrogenation , borohydride , hydrogen , metal , materials science , hydrogen storage , inorganic chemistry , analytical chemistry (journal) , chemistry , metallurgy , catalysis , organic chemistry
Due to its high hydrogen density (14.8 wt %) and low dehydrogenation peak temperature (130 °C), Zr(BH 4 ) 4 ⋅ 8 NH 3 is considered to be one of the most promising hydrogen‐storage materials. To further decrease its dehydrogenation temperature and suppress its ammonia release, a strategy of introducing LiBH 4 and Mg(BH 4 ) 2 was applied to this system. Zr(BH 4 ) 4 ⋅ 8 NH 3 –4 LiBH 4 and Zr(BH 4 ) 4 ⋅ 8 NH 3 –2 Mg(BH 4 ) 2 composites showed main dehydrogenation peaks centered at 81 and 106 °C as well as high hydrogen purities of 99.3 and 99.8 mol % H 2 , respectively. Isothermal measurements showed that 6.6 wt % (within 60 min) and 5.5 wt % (within 360 min) of hydrogen were released at 100 °C from Zr(BH 4 ) 4 ⋅ 8 NH 3 –4 LiBH 4 and Zr(BH 4 ) 4 ⋅ 8 NH 3 –2 Mg(BH 4 ) 2 , respectively. The lower dehydrogenation temperatures and improved hydrogen purities could be attributed to the formation of the diammoniate of diborane for Zr(BH 4 ) 4 ⋅ 8 NH 3 –4 LiBH 4 , and the partial transfer of NH 3 groups from Zr(BH 4 ) 4 ⋅ 8 NH 3 to Mg(BH 4 ) 2 for Zr(BH 4 ) 4 ⋅ 8 NH 3 –2 Mg(BH 4 ) 2 , which result in balanced numbers of BH 4 and NH 3 groups and a more active H δ + ⋅⋅⋅ − δ H interaction. These advanced dehydrogenation properties make these two composites promising candidates as hydrogen‐storage materials.