氢气储存
石墨烯
氧化物
成核
材料科学
纳米晶材料
亚稳态
氢
硼氢化
化学工程
热力学
化学物理
纳米技术
化学
合金
有机化学
冶金
催化作用
工程类
物理
作者
Sohee Jeong,Tae Wook Heo,Julia Oktawiec,Rongpei Shi,ShinYoung Kang,J. L. White,Andreas Schneemann,Edmond W. Zaia,Liwen F. Wan,Keith G. Ray,Yi‐Sheng Liu,Vitalie Stavila,Jinghua Guo,Jeffrey R. Long,Brandon C. Wood,Jeffrey J. Urban
出处
期刊:ACS Nano
[American Chemical Society]
日期:2020-01-10
卷期号:14 (2): 1745-1756
被引量:30
标识
DOI:10.1021/acsnano.9b07454
摘要
Magnesium borohydride (Mg(BH4)2, abbreviated here MBH) has received tremendous attention as a promising onboard hydrogen storage medium due to its excellent gravimetric and volumetric hydrogen storage capacities. While the polymorphs of MBH—alpha (α), beta (β), and gamma (γ)—have distinct properties, their synthetic homogeneity can be difficult to control, mainly due to their structural complexity and similar thermodynamic properties. Here, we describe an effective approach for obtaining pure polymorphic phases of MBH nanomaterials within a reduced graphene oxide support (abbreviated MBHg) under mild conditions (60–190 °C under mild vacuum, 2 Torr), starting from two distinct samples initially dried under Ar and vacuum. Specifically, we selectively synthesize the thermodynamically stable α phase and metastable β phase from the γ-phase within the temperature range of 150–180 °C. The relevant underlying phase evolution mechanism is elucidated by theoretical thermodynamics and kinetic nucleation modeling. The resulting MBHg composites exhibit structural stability, resistance to oxidation, and partially reversible formation of diverse [BH4]− species during de- and rehydrogenation processes, rendering them intriguing candidates for further optimization toward hydrogen storage applications.
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