A datamining approach to predict the formation enthalpy for rare-earth dihydrides REH2 (RE = Ce,Pr,Dy)

Benyelloul, Kamel; Seddik, L.; Bouhadda, Y.; Bououdina, M.; Fenineche, N.; Aourag, H.; Bouhafs, B.

doi:10.1016/j.ijhydene.2016.04.018

Cited by 11 publications

(1 citation statement)

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“…Reported in the literature enthalpies of formation of REH 2 vary from À224 ± 12 kJ/mol for ErH 2 , e 213 to À220 for DyH 2 [7,23] and À219 ± 12 kJ/mol for HoH 2 [8]. It can be seen that the enthalpies of formation for these three RE dihydrides have very close values and thus well agree with the similar values of peak temperatures from TDS studies when the data were collected in the same regimes.…”

Section: Hydrogen Desorption From Reh 3 Hydrides Studied By Thermal Dsupporting

confidence: 78%

Thermal desorption spectroscopy studies of hydrogen desorption from rare earth metal trihydrides REH3 (RE=Dy, Ho, Er)

Suwarno

Lototskyy

Yartys

2020

Journal of Alloys and Compounds

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Rare earth (RE) metals form two stoichiometric hydrides, REH 2 and REH 3 , and for the yttrium group of RE transformation of a FCC (REH 2) into an HCP (REH 3) lattice takes place during the second step of hydrogenation REH 2 þ ½ H 2 / REH 3. Earlier studies of the hydrogen desorption properties of the rare earth hydrides were limited to Y and RE ¼ La, Ce, Pr, Nd, Sm, Gd, Tb and Er. The present work is focused on the studies of the kinetics and mechanism of hydrogen desorption from trihydrides of heavy rare earths, DyH 3 , HoH 3, and ErH 3. The Thermal Desorption Spectroscopy (TDS) studies were performed at pressures below 1 Â 10 À5 mbar during linear heating from room temperature to 1173 K at different heating rates ranging from 1 to 5.5 K/min. Hydrogen desorption traces show the presence of two main events with the low-temperature peak appearing below 573 K, while the second peak is positioned at 1083e1159 K, with the peak temperatures gradually increasing following the rise of the heating rate. Fitting of the peak temperatures in the TDS spectra using the Kissinger method yielded activation energies of hydrogen desorption for both hydrogen desorption events. For DyH 3 and ErH 3 , the shapes of the TDS spectra appear to be well described by a phase-stuctural transformation following a model of nucleation and growth, while for HoH 3 the dehydrogenation mechanism includes a phase boundary reaction. This applied model of phase-structural transformations shows differences in dimensionality and rate-limiting steps as related to the studied compound and the desorption events, REH 3 / REH 2 or REH 2 / RE.

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Section: Hydrogen Desorption From Reh 3 Hydrides Studied By Thermal Dsupporting

confidence: 78%