title: Metal-Borohydride-Modified Zr(BH4 )4 ⋅8 NH3 : Low-Temperature Dehydrogenation Yielding Highly Pure Hydrogen.
abstract: Due to its high hydrogen density (14.8 wt %) and low dehydrogenation peak temperature (130 °C), Zr(BH4 )4 ⋅8 NH3 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 LiBH4 and Mg(BH4 )2 was applied to this system. Zr(BH4 )4 ⋅8 NH3 -4 LiBH4 and Zr(BH4 )4 ⋅8 NH3 -2 Mg(BH4 )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 % H2 , 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(BH4 )4 ⋅8 NH3 -4 LiBH4 and Zr(BH4 )4 ⋅8 NH3 -2 Mg(BH4 )2 , respectively. The lower dehydrogenation temperatures and improved hydrogen purities could be attributed to the formation of the diammoniate of diborane for Zr(BH4 )4 ⋅8 NH3 -4 LiBH4 , and the partial transfer of NH3 groups from Zr(BH4 )4 ⋅8 NH3 to Mg(BH4 )2 for Zr(BH4 )4 ⋅8 NH3 -2 Mg(BH4 )2 , which result in balanced numbers of BH4 and NH3 groups and a more active H(δ+) ⋅⋅⋅(-δ) H interaction. These advanced dehydrogenation properties make these two composites promising candidates as hydrogen-storage materials.
authors: School of Materials Science and Engineering and Key Laboratory of Advanced Energy Storage Materials of Guangdong Province, South China University of Technology, Wushan Road, Tianhe District, Guangzhou 510641 (P.R. China).
authors: Jianmei
authors: J
authors: Huang
authors: School of Materials Science and Engineering and Key Laboratory of Advanced Energy Storage Materials of Guangdong Province, South China University of Technology, Wushan Road, Tianhe District, Guangzhou 510641 (P.R. China). meouyang@scut.edu.cn.
authors: Liuzhang
authors: L
authors: Ouyang
authors: Australian Synchrotron, 800 Blackburn Rd., Clayton 3168 (Australia).
authors: Qinfen
authors: Q
authors: Gu
authors: Department of Materials Science, Fudan University, Handan Road, Yangpu Distric, Shanghai 200433 (P.R. China). yuxuebin@fudan.edu.cn.
authors: Xuebin
authors: X
authors: Yu
authors: School of Materials Science and Engineering and Key Laboratory of Advanced Energy Storage Materials of Guangdong Province, South China University of Technology, Wushan Road, Tianhe District, Guangzhou 510641 (P.R. China).
authors: Min
authors: M
authors: Zhu
keywords: borohydrides; hydrides; hydrogen; hydrogen storage; zirconium