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Room Temperature Hydrogen Absorption of Mg/MgH2 Catalyzed by BaTiO3
The Journal of Physical Chemistry C ( IF 3.7 ) Pub Date : 2021-09-03 , DOI: 10.1021/acs.jpcc.1c05560
Joshua Adedeji Bolarin 1, 2 , Zhao Zhang 1 , Hujun Cao 1 , Zhi Li 3 , Teng He 1 , Ping Chen 1
Affiliation  

This paper seeks to present notable insights into the catalytic behavior of a ferroelectric BaTiO3 nanomaterial at the boundary plane in the separation of MgH2 starting from 185 °C. The synergy between mechanical milling and enhanced electronic distribution at the surface of BaTiO3 aided magnesium to a remarkable absorption of 4.5 wt % H2 at room temperature under 30 bar within 20 h. The composite released H2 ∼ 5.7 wt % in 15 min at 310 °C and ∼5.1 wt % in 90 min at 250 °C. The lowered activation energy of decomposition was calculated to be ∼60 kJ/mol with a decomposition enthalpy of 72.3 kJ/mol-H2. The composite reversibly produced ∼5.7 wt % H2 across 20 cycles in less than 120 h at 300 °C. As revealed by detailed experimental results, the interplay between +4 and +3 states of titanium at “111” twin boundaries of BaTiO3, and the formation of oxygen vacancies, play an important role in improving the sorption kinetics and the reversibility of Mg/MgH2. Meanwhile, the anomalous ferroelectric character of the +2 state of barium around Ti–O and Mg after milling of BaTiO3 is also believed to slightly enhance MgH2 desorption enthalpy via a chemisorption process. Our findings have brought MgH2 a few steps closer to practical applications.

中文翻译:

BaTiO3催化Mg/MgH2的室温吸氢

本文旨在对铁电 BaTiO 3纳米材料在185 °C 开始分离 MgH 2时在边界面上的催化行为提出重要见解。机械研磨和 BaTiO 3表面增强的电子分布之间的协同作用有助于镁在室温下 30 巴下在 20 小时内显着吸收 4.5 wt% H 2。该复合材料在 310 °C 下在 15 分钟内释放了约 5.7 wt% 的H 2 ,在 250 °C 下在 90 分钟内释放了约 5.1 wt%。降低的分解活化能计算为~60 kJ/mol,分解焓为72.3 kJ/mol-H 2。复合材料可逆地产生~5.7 wt % H 2在 300 °C 下,在不到 120 小时内完成 20 个循环。详细的实验结果表明,在 BaTiO 3 的“111”孪晶界上钛的 +4 和 +3 态之间的相互作用以及氧空位的形成,在改善 Mg/ MgH 2。同时,在研磨 BaTiO 3后,Ti-O 和 Mg 周围的钡的 +2 态异常铁电特性也被认为通过化学吸附过程略微提高了 MgH 2解吸焓。我们的发现使 MgH 2更接近实际应用。
更新日期:2021-09-16
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