Dehydrogenation kinetics of magnesium hydride investigated by DFT and experiment AITranslate

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DOI：https://doi.org/10.1016/j.commatsci.2010.02.048

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Periodic density functional theory (DFT) 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 H2 recombination on the pure surface. It is suggested that the rate-controlling step is recombination of H2 on the MgH2 surface.