Structure and Deuterium Desorption from Ca3Mg2Ni13 Deuteride: A Neutron Diffraction Study

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• 作者：Qingan Zhang ; Dalin Sun ; Junxian Zhang ; Michel Latroche ; Liuzhang Ouyang ; Min Zhu
• 刊名：Journal of Physical Chemistry C
• 出版年：2014
• 出版时间：March 6, 2014
• 年：2014
• 卷：118
• 期：9
• 页码：4626-4633
• 全文大小：389K
• 年卷期：v.118,no.9(March 6, 2014)
• ISSN：1932-7455

文摘

The Ca₃Mg₂Ni₁₃ unit cell can be viewed as the stacking of three blocks along the c axis. Each block is composed of two sub-blocks; one sub-block contains one layer of a [CaMgNi₄] unit, and the other sub-block consists of one layer of a [CaMgNi₄] unit and one layer of a [CaNi₅] unit. To understand the deuterium release from the Ca₃Mg₂Ni₁₃ deuteride, crystal structures of Ca₃Mg₂Ni₁₃D_15.6, Ca₃Mg₂Ni₁₃D_5.9, and Ca₃Mg₂Ni₁₃D_0.3 corresponding to before, during, and after deuterium desorption were determined by neutron diffraction. In Ca₃Mg₂Ni₁₃D_15.6, D atoms occupy interstitial sites within [CaNi₅] and [CaMgNi₄] units as well as sites at two unit borders. Upon deuterium desorption, the D atoms located at unit borders are released first. Then D atoms located within [CaNi₅] and [CaMgNi₄] units are simultaneously released which leads to the coexistence of Ca₃Mg₂Ni₁₃D_5.9 and a deuterium-poor solid solution phase. With further desorption, Ca₃Mg₂Ni₁₃D_5.9 transforms into Ca₃Mg₂Ni₁₃D_0.3 where D atoms reside in [CaNi₅] units only.