Møller Kasper T, Jørgensen Mathias, Fogh Alexander S, Jensen Torben R
Interdisciplinary Nanoscience Center (iNANO) and Department of Chemistry, University of Aarhus, DK-8000 Aarhus, Denmark.
Dalton Trans. 2017 Sep 12;46(35):11905-11912. doi: 10.1039/c7dt02405c.
A new synthesis method of samarium borohydride, Sm(BH), using tetrahydrofuran borane, THF-BH, and samarium hydride, SmH, has been demonstrated and verified. The synthesised Sm(BH) was mechanochemically treated with MBH, M = K, Rb, Cs. Initially, the formation of KSm(BH) is observed while subsequent heat treatment is necessary to form MSm(BH), M = Rb, Cs. The new compounds crystallise in orthorhombic unit cells adopting perovskite-type 3D frameworks containing distorted [Sm(BH)] octahedra. In situ X-ray diffraction studies reveal two second-order polymorphic transitions of α-CsSm(BH)via a tetragonal intermediate, α'-CsSm(BH), into a cubic high-temperature polymorph, β-CsSm(BH), resembling an ideal perovskite structure. The new compounds, MSm(BH), are thermally stable up to T ∼ 280 °C after which they decompose into mainly MBH, SmH and possibly SmB and SmBH. Finally, after three cycles of hydrogen release and uptake, the storage capacity was 1.0 wt% for KSm(BH) and 0.84 wt% for RbSm(BH) and CsSm(BH).
一种使用四氢呋喃硼烷（THF-BH）和氢化钐（SmH）合成硼氢化钐（Sm(BH)）的新方法已得到证实和验证。将合成的Sm(BH)与MBH（M = K、Rb、Cs）进行机械化学处理。最初，观察到形成了KSm(BH)，而后续需要进行热处理以形成MSm(BH)（M = Rb、Cs）。这些新化合物在正交晶胞中结晶，采用钙钛矿型三维框架结构，其中包含扭曲的[Sm(BH)]八面体。原位X射线衍射研究表明，α-CsSm(BH)通过四方中间相α'-CsSm(BH)发生两次二级多晶型转变，转变为立方高温多晶型β-CsSm(BH)，类似于理想的钙钛矿结构。新化合物MSm(BH)在高达T ∼ 280 °C时热稳定，之后它们主要分解为MBH、SmH，可能还有SmB和SmBH。最后，经过三次氢释放和吸收循环后，KSm(BH)的储氢容量为1.0 wt%，RbSm(BH)和CsSm(BH)的储氢容量为0.84 wt%。
