Investigation of surface and near-surface effects on hydrogen desorption kinetics of MgH2
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Kurko, Sandra V.Milanović, Igor
Grbović-Novaković, Jasmina
Ivanović, Nenad
Novaković, Nikola
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Desorption of hydrogen atoms from the (110) surface of rutile magnesium hydride (MgH2) was investigated using density functional theory (DFT) and pseudopotential method. System was represented by (110) (2x2) slab MgH2 supercell with 12 atomic layers along the z-axis. The H-desorption was modeled by the successive release of the four two-fold bonded H atoms from the (110) surface of MgH2. Dependence of the H-desorption energy on number and configuration of remaining surface hydrogen atoms has been determined. The features of the H atoms diffusion from the bulk towards the surface have been investigated, too. The results suggest that decrease in number of surface H atoms generally lowers the H-desorption energy in each desorption step and that both the H-H and the Mg-H interatomic interactions strongly influence the H-desorption process. The hydrogen vacancy formation energy in the first three sub-surface layers also exhibits a pronounced dependence on concentration. These findings lead ...to the conclusion that tendency of the MgH2 (110) surface to preserve a maximum possible surface H concentration in its most stable configuration is the limiting factor for the H-desorption kinetics. In principle, the obtained results allow us to determine preferred paths of surface and subsurface H-diffusion for a wide range of H concentrations and the principle features of the MgH2 dehydrogenation process, at least for the H-rich region. Being rather comprehensive, the approach is applicable for other metal hydrides, as well. Copyright (C) 2013, Hydrogen Energy Publications, LLC. Published by Elsevier Ltd. All rights reserved.
Keywords:
MgH2 / Hydrogen kinetics / ab initio calculations / Surface effectsSource:
International Journal of Hydrogen Energy, 2014, 39, 2, 862-867Funding / projects:
- Synthesis, processing and characterization of nanostructured materials for application in the field of energy, mechanical engineering, environmental protection and biomedicine (RS-MESTD-Integrated and Interdisciplinary Research (IIR or III)-45012)
DOI: 10.1016/j.ijhydene.2013.10.107
ISSN: 0360-3199; 1879-3487
WoS: 000331156200025
Scopus: 2-s2.0-84890432415
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VinčaTY - JOUR AU - Kurko, Sandra V. AU - Milanović, Igor AU - Grbović-Novaković, Jasmina AU - Ivanović, Nenad AU - Novaković, Nikola PY - 2014 UR - https://vinar.vin.bg.ac.rs/handle/123456789/5875 AB - Desorption of hydrogen atoms from the (110) surface of rutile magnesium hydride (MgH2) was investigated using density functional theory (DFT) and pseudopotential method. System was represented by (110) (2x2) slab MgH2 supercell with 12 atomic layers along the z-axis. The H-desorption was modeled by the successive release of the four two-fold bonded H atoms from the (110) surface of MgH2. Dependence of the H-desorption energy on number and configuration of remaining surface hydrogen atoms has been determined. The features of the H atoms diffusion from the bulk towards the surface have been investigated, too. The results suggest that decrease in number of surface H atoms generally lowers the H-desorption energy in each desorption step and that both the H-H and the Mg-H interatomic interactions strongly influence the H-desorption process. The hydrogen vacancy formation energy in the first three sub-surface layers also exhibits a pronounced dependence on concentration. These findings lead to the conclusion that tendency of the MgH2 (110) surface to preserve a maximum possible surface H concentration in its most stable configuration is the limiting factor for the H-desorption kinetics. In principle, the obtained results allow us to determine preferred paths of surface and subsurface H-diffusion for a wide range of H concentrations and the principle features of the MgH2 dehydrogenation process, at least for the H-rich region. Being rather comprehensive, the approach is applicable for other metal hydrides, as well. Copyright (C) 2013, Hydrogen Energy Publications, LLC. Published by Elsevier Ltd. All rights reserved. T2 - International Journal of Hydrogen Energy T1 - Investigation of surface and near-surface effects on hydrogen desorption kinetics of MgH2 VL - 39 IS - 2 SP - 862 EP - 867 DO - 10.1016/j.ijhydene.2013.10.107 ER -
@article{ author = "Kurko, Sandra V. and Milanović, Igor and Grbović-Novaković, Jasmina and Ivanović, Nenad and Novaković, Nikola", year = "2014", abstract = "Desorption of hydrogen atoms from the (110) surface of rutile magnesium hydride (MgH2) was investigated using density functional theory (DFT) and pseudopotential method. System was represented by (110) (2x2) slab MgH2 supercell with 12 atomic layers along the z-axis. The H-desorption was modeled by the successive release of the four two-fold bonded H atoms from the (110) surface of MgH2. Dependence of the H-desorption energy on number and configuration of remaining surface hydrogen atoms has been determined. The features of the H atoms diffusion from the bulk towards the surface have been investigated, too. The results suggest that decrease in number of surface H atoms generally lowers the H-desorption energy in each desorption step and that both the H-H and the Mg-H interatomic interactions strongly influence the H-desorption process. The hydrogen vacancy formation energy in the first three sub-surface layers also exhibits a pronounced dependence on concentration. These findings lead to the conclusion that tendency of the MgH2 (110) surface to preserve a maximum possible surface H concentration in its most stable configuration is the limiting factor for the H-desorption kinetics. In principle, the obtained results allow us to determine preferred paths of surface and subsurface H-diffusion for a wide range of H concentrations and the principle features of the MgH2 dehydrogenation process, at least for the H-rich region. Being rather comprehensive, the approach is applicable for other metal hydrides, as well. Copyright (C) 2013, Hydrogen Energy Publications, LLC. Published by Elsevier Ltd. All rights reserved.", journal = "International Journal of Hydrogen Energy", title = "Investigation of surface and near-surface effects on hydrogen desorption kinetics of MgH2", volume = "39", number = "2", pages = "862-867", doi = "10.1016/j.ijhydene.2013.10.107" }
Kurko, S. V., Milanović, I., Grbović-Novaković, J., Ivanović, N.,& Novaković, N.. (2014). Investigation of surface and near-surface effects on hydrogen desorption kinetics of MgH2. in International Journal of Hydrogen Energy, 39(2), 862-867. https://doi.org/10.1016/j.ijhydene.2013.10.107
Kurko SV, Milanović I, Grbović-Novaković J, Ivanović N, Novaković N. Investigation of surface and near-surface effects on hydrogen desorption kinetics of MgH2. in International Journal of Hydrogen Energy. 2014;39(2):862-867. doi:10.1016/j.ijhydene.2013.10.107 .
Kurko, Sandra V., Milanović, Igor, Grbović-Novaković, Jasmina, Ivanović, Nenad, Novaković, Nikola, "Investigation of surface and near-surface effects on hydrogen desorption kinetics of MgH2" in International Journal of Hydrogen Energy, 39, no. 2 (2014):862-867, https://doi.org/10.1016/j.ijhydene.2013.10.107 . .