Ab initio alloying of Mg for hydrogen storage

2008-12-01
Kecik, Deniz
Aydınol, Mehmet Kadri
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A candidate hydrogen storing material should have high storage capacity and fast dehydrogenation kinetics. On this basis, magnesium hydride (MgH 2) is an outstanding compound with 7.6 wt % storage capacity, despite its slow dehydriding kinetics and high desorption temperature. Therefore in this study, formation energies of alloyed bulk MgH2, adsorption energies on alloyed magnesium (Mg) and MgH2 surface structures were calculated by total energy pseudopotential methods. Also, the effect of substitutionally placed dopants to the dissociation of hydrogen molecule (H 2) at the surface of Mg was investigated via Molecular Dynamics (MD). The results show that 31 out of 32 selected dopants decreased the formation energy of bulk MgH2, within a range of ∼ 37 kJ/mol-H2 where only Sr did not display any such effect. The most favorable elements in this respect are; P, K, Tl, Si, Sn, Ag and Pb. Moreover, surface adsorption energy values display that all elements are adsorbed substitutionally on the clean (0001) surface of Mg where adsorption on MgH2 (001) surface is possible only for alloying elements other than Zn, Au, In, Ag, Li, Tl, Cd, Na and K. Finally, results of MD simulations point out that the elements giving rise to me dissociation of hydrogen molecule came out to be Ti, V, Cr, Mn, Fe, Co, Ni, Zr, Nb, Mo, Ru, Rh ve Hf.
Magnesium compounds
https://www.scopus.com/inward/record.uri?partnerID=HzOxMe3b&scp=70350317438&origin=inward
https://hdl.handle.net/11511/79875
2008 MRS Spring Meeting
Department of Metallurgical and Materials Engineering, Conference / Seminar

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Citation Formats
D. Kecik and M. K. Aydınol, “Ab initio alloying of Mg for hydrogen storage,” San Francisco, CA; United States, 2008, vol. 1098, Accessed: 00, 2021. [Online]. Available: https://www.scopus.com/inward/record.uri?partnerID=HzOxMe3b&scp=70350317438&origin=inward.
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