Ning Hua, Deng Junlong, Meng Zhipeng, Zhou Xingyu, Lan Zhiqiang, Guo Jin
College of Mathematics and Physics, Guangxi University for Nationalities, Nanning 530006, P. R. China.
Guangxi Colleges and Universities Key Laboratory of Novel Energy Materials and Related Technology, Guangxi Novel Battery Materials Research Center of Engineering Technology, College of Physics Science and Technology, Guangxi University, Nanning 530004, P. R. China.
ACS Appl Mater Interfaces. 2021 Mar 17;13(10):11901-11910. doi: 10.1021/acsami.0c20212. Epub 2021 Mar 4.
The MgAl-BaO composite is synthesized via mechanical milling and the effect of BaO on the hydrogen sorption properties of MgAl is studied. Experimentally, we prepare the MgAl-Ba, MgAl-BaO, MgAl-BaF, and MgAl-BaCl mixtures and find that the MgAl-BaO composite shows a superior hydrogen storage performance. For instance, the hydrogenation (dehydrogenation) enthalpy of the MgAl decreases from 62.4 (91.2) to 58.6 (71.7) kJ mol after adding BaO. When 1.0 wt % of H is absorbed/desorbed, the hydrogen absorption/desorption temperature of the MgAl-BaO is 181/271 °C, which is 73/37 °C lower than that of the MgAl. Furthermore, the catalytic mechanism of BaO on the hydrogenation of MgAl (110) surface is investigated by density functional theory (DFT). Calculations indicate that compared with the MgAl (110) surface, the adsorption energy and dissociation barrier of hydrogen on the MgAl-BaO (110) surface are both improved significantly. Our experimental and theoretical results are helpful for understanding the effect of metal oxide on hydrogen storage properties of MgAl.
通过机械球磨合成了MgAl-BaO复合材料，并研究了BaO对MgAl储氢性能的影响。实验中，我们制备了MgAl-Ba、MgAl-BaO、MgAl-BaF和MgAl-BaCl混合物，发现MgAl-BaO复合材料表现出优异的储氢性能。例如，添加BaO后，MgAl的氢化（脱氢）焓从62.4（91.2）kJ/mol降至58.6（71.7）kJ/mol。当吸收/解吸1.0 wt%的H时，MgAl-BaO的吸氢/解吸温度为181/271°C，比MgAl低73/37°C。此外，采用密度泛函理论（DFT）研究了BaO对MgAl（110）表面氢化的催化机理。计算表明，与MgAl（110）表面相比，H在MgAl-BaO（110）表面的吸附能和解离势垒均有显著提高。我们的实验和理论结果有助于理解金属氧化物对MgAl储氢性能的影响。
