Hydrogenation properties of Hf–Ni intermetallics – Experimental and theoretical investigation

The hydrogenation properties of HfNi and Hf 2Ni 7 intermetallics were investigated at the constant pressure of 1 bar and in the temperature ranges 373–573 K for HfNi and 323–473 K for Hf 2Ni 7. The kinetic parameters, rate constants and activation energies of the absorption processes were determined...

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Bibliographic Details
Published in:International journal of hydrogen energy 2011-08, Vol.36 (17), p.10771-10778
Main Authors: Stojić, Dragica Lj, Ćirić, Katarina D., Cekić, Božidar Đ., Koteski, Vasil J., Zec, Slavica P., Bogdanov, Žarko D.
Format: Article
Language:English
Subjects:
Activation energy
Alternative fuels. Production and utilization
Applied sciences
Density functional theory
Energy
Exact sciences and technology
FP-LAPW calculations
Fuels
Hf 2Ni 7
HfNi
Hydriding capacity
Hydrogen
Hydrogen absorption kinetic
Hydrogen atoms
Hydrogen storage
Hydrogenation
Intermetallics
Mathematical analysis
Plane waves
Rate constants
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Summary:The hydrogenation properties of HfNi and Hf 2Ni 7 intermetallics were investigated at the constant pressure of 1 bar and in the temperature ranges 373–573 K for HfNi and 323–473 K for Hf 2Ni 7. The kinetic parameters, rate constants and activation energies of the absorption processes were determined. Maximal hydrogen absorption, i.e., number of hydrogen atoms absorbed per metal atom, H/ M, are 1.05 and 0.04 achieved at 373 K for HfNi and Hf 2Ni 7, respectively. Multiple hydriding/dehydriding was found to influence the improvement of the kinetic parameters. XRD and SEM methods were used to investigate the structural and morphological changes of the samples due to hydrogen absorption. The thermodynamic parameters of hydriding together with the structural properties of the intermetallics and their hydrides, calculated using the full-potential linearized augmented plane waves (FP-LAPW) code based on the density functional theory (DFT), were utilized for the sake of explaining the experimental investigations. ► Hydrogen absorption kinetics for HfNi and Hf 2Ni 7 at the 1 bar pressure was examined. ► Maximal H/ M values are 1.05 and 0.04 for HfNi and Hf 2Ni 7 respectively, at 373 K. ► DFT calculations are performed for Hf 2Ni 7. ► Hydrogen storage in Hf–Ni intermetallics is discussed in relation to DFT results.
ISSN:0360-3199
1879-3487
DOI:10.1016/j.ijhydene.2011.05.131