Dehydrogenation kinetics of magnesium hydride investigated by DFT and experiment

作者：Wu, Guangxin; Zhang, Jieyu^*; Li, Qian; Wu, Yongquan; Chou, Kuochih; Bao, Xinhua

来源：Computational Materials Science, 2010, 49(1): S144-S149.

DOI：10.1016/j.commatsci.2010.02.048

• Magnesium hydride
• First-principles calculations
• Dehydrogenation pathways
• Energy barriers

Periodic density functional theory (OFT) and nudged elastic Band (NEB) method have been used to investigate the hydrogen desorption on MgH2(0 0 1) and MgH2(1 1 0) surface as a first step towards understanding the dehydrogenation cycle. A study of reaction barriers for three and five pathways of MgH2(0 0 1) and MgH2(1 1 0) surface have been performed. The most favorable desorption channel needs activation energies of approximately 1.60 eV with H atoms binding on the same Mg atoms on the MgH2(1 1 0) surface. Meanwhile, the MgH2 sample was prepared by ball milling treatment and Chou method was used to investigate the hydrogen desorption kinetic mechanism of MgH2. The obtained activation energies are 1.58 +/- 0.6 eV for H-2 recombination on the pure surface. It is suggested that the rate-controlling step is recombination of H-2 on the MgH2 surface.

• 出版日期2010-7
• 单位上海大学; 北京科技大学