Effects of Li on hydrogen absorption properties of Mg17Al12(110) surface: A density functional theory study. (27th September 2018)

• Record Type: Journal Article
• Authors: Zhou, Xingyu; Ma, Shuyuan; Xu, Shoulei; Guo, Jin; Ning, Hua
• Is Part Of: International journal of hydrogen energy. Volume 43:Number 39(2018)
• Page Start: 18330
• Page End: 18338
• Publication Date: 2018-09-27
• Subjects: Density functional theory -- Mg17Al12 -- Hydrogen storage -- Adsorption -- Dissociation; Hydrogen as fuel -- Periodicals; Hydrogène (Combustible) -- Périodiques; Hydrogen as fuel; Periodicals; 665.81
• DOI: 10.1016/j.ijhydene.2018.07.172
• Languages: English
• ISSNs: 0360-3199

Abstract

Abstract: On the basis of density functional theory (DFT), the catalytic effects of Li on hydrogen absorption properties of the Mg17 Al12 (110) surfaces are studied. The Li-containing Mg17 Al12 (110) surfaces were composed of the Li-substituted and Li-adsorbed systems, namely Mg16 LiAl12 (110) and Mg17 Al12 (110)/Li surfaces, respectively. Calculations indicate that adsorption energies of H (H2 ) on the Mg17 Al12 (110) surfaces with a low amount of Li were significantly improved relative to hydrogen on the clean surface. Especially, the energy of H (H2 ) on the Mg17 Al12 (110)/Li system was −0.68 (−0.48) eV. Moreover, the addition of Li remarkably promotes the dissociative properties of H2 on the (110) surface. The barrier energy of H2 dissociation on the Mg17 Al12 (110)/Li surface was 0.14 eV, which was much lower than that (0.87 eV) on the pure surface. Analysis of electronic structures reveals that the H-s orbital hybridized with the Mg-s evidently in the Li-containing systems. The formation of LiH bond and the interaction between H2 and Li atom may explain the enhanced hydrogenation properties of Mg17 Al12 (110)/Li surface. Graphical abstract: Highlights: H2 adsorption and dissociation on Li-containing Mg17 Al12 (110) surface are studied. Hydrogenation properties of Mg17 Al12 (110) surfaces were improved by adding Li. H2 dissociated and adsorbed on the Li-adsorbed system easily. H atom bonded with Mg and Li atoms at the same time on Li-adsorbed surface.