Hydrogen Storage in AB2 Laves Phase (A ) Zr, Ti; B ) Ni, Mn, Cr, V): Binding Energy

S. B. GESARI; M. E. PRONSATO; A, VISINTIN; A. JUAN

JOURNAL OF PHYSICAL CHEMISTRY C

AMER CHEMICAL SOC

Lugar: Washington, DC ; Año: 2010 vol. 114 p. 16832 - 16836

1932-7447

Theoretical studies on the total energy, electronic structure, and bonding of the Zr0.9Ti0.1NiMn0.5Cr0.25V0.25 0.9Ti0.1NiMn0.5Cr0.25V0.25 alloy and its hydrides were performed using density functional theory calculations. This alloy crystallizes in the C14 Laves phase. To determine the equilibrium structural parameters for this compound, we performed lattice constants optimization. The optimized c/a ratio was found in good agreement with experimental data. When hydrogen is introduced in the AB2 matrix, there are different sites to localize it with a variety of local environments. We found that A2B2 sites are preferentially occupied. After hydrogenation, the volume of the alloy increases, whereas the binding energy remains practically the same up to 3.5 H/FU, indicating little interaction among hydrogen atoms. The electronic structure of AB2 and AB2H3.5 phases is also analyzed. alloy increases, whereas the binding energy remains practically the same up to 3.5 H/FU, indicating little interaction among hydrogen atoms.  0.9Ti0.1NiMn0.5Cr0.25V0.25 alloy and its hydrides were performed using density functional theory calculations. This alloy crystallizes in the C14 Laves phase. To determine the equilibrium structural parameters for this compound, we performed lattice constants optimization. The optimized c/a ratio was found in good agreement with experimental data. When hydrogen is introduced in the AB2 matrix, there are different sites to localize it with a variety of local environments. We found that A2B2 sites are preferentially occupied. After hydrogenation, the volume of the alloy increases, whereas the binding energy remains practically the same up to 3.5 H/FU, indicating little interaction among hydrogen atoms. The electronic structure of AB2 and AB2H3.5 phases is also analyzed. alloy increases, whereas the binding energy remains practically the same up to 3.5 H/FU, indicating little interaction among hydrogen atoms.