Selective reversible hydrogenation of Mg(B3H8)2/MgH2 to Mg(BH4)2: Pathway to reversible borane-based hydrogen storage?

Marina Chong, Motoaki Matsuo, Shin Ichi Orimo, Tom Autrey, Craig M. Jensen

研究成果: Article査読

36 被引用数 (Scopus)

抄録

Mg(B3H8)2·2THF (THF = tetrahydrofuran) was prepared by the addition of BH3·THF to Mg/Hg amalgam. Heating a 1:2 molar mixture of Mg(B3H8)2·2THF and MgH2 to 200 °C under 5 MPa H2 for 2 h leads to nearly quantitative conversion to Mg(BH4)2. The differential scanning calorimetry profile of the reaction measured under 5 MPa H2 shows an initial endothermic feature at 65 °C for a phase change of the compound followed by a broad exothermic feature that reaches a maximum at 130 °C corresponding to the hydrogenation of Mg(B3H8)2 to Mg(BH4)2. Heating Mg(B3H8)2·2THF to 200 °C under 5 MPa H2 pressure in the absence of MgH2 gives predominantly MgB12H12 as well as significant amounts of MgB10H10 and Mg(BH4)2. Hydrogenation of a mixture of Mg(B3H8)2·2THF and LiH in a 1:4 molar ratio at 130 °C under 5 MPa H2 yields [B12H12]2- in addition to [BH4]-, while a 1:4 molar ratio of Mg(B3H8)2·2THF and NaH yields [BH4]- and a new borane, likely [B2H7]-. Hydrogenation of the NaH-containing mixture at 130 °C gives primarily the alternative borane, indicating it is an intermediate in the two-step conversion of the triborane to [BH4]-. The solvent-free triborane Mg(B3H8)2, derived from the low-temperature dehydrogenation of Mg(BH4)2, also produces Mg(BH4)2, but higher temperature and pressure is required to effect the complete transformation of the Mg(B3H8)2. These results show that the reversible transformation of the triborane depends on the stability of the metal hydride. The more stable the metal hydride, that is, LiH > NaH > MgH2, the lower is the regeneration efficiency.

本文言語English
ページ(範囲)4120-4125
ページ数6
ジャーナルInorganic chemistry
54
8
DOI
出版ステータスPublished - 2015 4 20

ASJC Scopus subject areas

  • 物理化学および理論化学
  • 無機化学

フィンガープリント

「Selective reversible hydrogenation of Mg(B<sub>3</sub>H<sub>8</sub>)<sub>2</sub>/MgH<sub>2</sub> to Mg(BH<sub>4</sub>)<sub>2</sub>: Pathway to reversible borane-based hydrogen storage?」の研究トピックを掘り下げます。これらがまとまってユニークなフィンガープリントを構成します。

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