Crystal Structure and Cyclic Hydrogenation Property of Pr4MgNi19

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• 作者：Kenji Iwase ; Naoyoshi Terashita ; Kazuhiro Mori ; Hitoshi Yokota ; Tetsuya Suzuki
• 刊名：Inorganic Chemistry
• 出版年：2013
• 出版时间：December 16, 2013
• 年：2013
• 卷：52
• 期：24
• 页码：14270-14274
• 全文大小：294K
• 年卷期：v.52,no.24(December 16, 2013)
• ISSN：1520-510X

文摘

The hydrogen absorption鈥揹esorption property and the crystal structure of Pr₄MgNi₁₉ was investigated by pressure鈥揷omposition isotherm measurement and X-ray diffraction (XRD). Pr₄MgNi₁₉ consisted of two phases: 52.9% Ce₅Co₁₉-type structure (3R) and 47.0% Gd₂Co₇-type structure (3R). Sm₅Co₁₉-type structure (2H) and Ce₂Ni₇-type structure (2H) were not observed in the XRD profile. The Mg atoms substituted at the Pr sites in a MgZn₂-type cell. The maximum hydrogen capacity reached 1.14 H/M (1.6 mass%) at 2 MPa. The hysteresis factor, Hf = ln(P_abs/P_des), was 1.50. The cyclic hydrogenation property of Pr₄MgNi₁₉ was investigated up to 1000 absorption鈥揹esorption cycles. After 250, 500, 750, and 1000 cycles, the retention rates of hydrogen were reduced to 94%, 92%, 91%, and 90%, respectively. These properties were superior to those of Pr₂MgNi₉ and Pr₃MgNi₁₄.