Deuterium absorption properties of V85Ni15 and evidence of isotope effect

Brutti, Sergio; Tosti, Silvano; Santucci, Alessia; Paolone, A.

doi:10.1016/j.ijhydene.2019.05.227

Cited by 4 publications

(10 citation statements)

References 26 publications

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“…The three strongest broad signals at about 41, 62 and 77 degrees can be indexed with Bragg reflections with Miller indexes (110), ( 200) and ( 211), possibly attributed to a body-centered-cubic (BCC) lattice, in line with our previous observation on a similar stoichiometry [11,12], and the attributions performed by other authors [7,21]. The broad undulation at 22-24 degrees has an apparent poor matching with any V-Ni ordered phase [11,12], and thus can be attributed to the glass sample holder or nanometric traces of V2O5. The Rietveld refinement performed on the XRD pattern, assuming a BCC lattice with atomic sites randomly occupied by V and N as well as the experimental stoichiometry, confirms the qualitative analysis of the XRD pattern.…”

Section: Stoichiometric and Structural Analysissupporting

confidence: 88%

“…The Rietveld refinement performed on the XRD pattern, assuming a BCC lattice with atomic sites randomly occupied by V and N as well as the experimental stoichiometry, confirms the qualitative analysis of the XRD pattern. The refinement procedure is in line with our previous approaches already reported in refs [11,12] and limits the fitting to three independent parameters (cubic lattice size, crystallite size and crystallite strain). The Rietveld refinement results are summarized in Table 2.…”

Section: Stoichiometric and Structural Analysismentioning

confidence: 74%

Section: Introductionmentioning

confidence: 99%

“…Recently, we investigated a V 85 Ni 15 alloy produced by induction melting, regarding its hydrogen and deuterium sorption properties [11,12]. It must be noted that the V-H and V-D systems have clear different phase diagrams, and this fact is also reflected in the V 85 Ni 15 alloy [11,12]. Moreover, this V-Ni alloy also has very fast absorption/desorption kinetics, suggesting that this material is a good candidate also for hydrogen purification [11,12].…”

Section: Introductionmentioning

confidence: 99%

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Mechanochemical Synthesis and Hydrogen Sorption Properties of a V-Ni Alloy

et al. 2022

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Vanadium can store large quantities of hydrogen (about 4 mass%). However, only half of it can be reversibly absorbed. To avoid this issue, various partial substitutions were previously proposed, such as Ni. In this work, we explore the synthesis of a V85Ni15 alloy by means of ball milling, a simpler and more scalable method compared to arc or induction melting usually applied for metal alloys. After ball milling the powders of the pure metals for 15 h in argon, SEM–EDX measurements confirmed the stoichiometry of the synthesized material, which has a typical particle dimension of the order of a few microns and is composed from the coalescence of nanometric primary particles. XRD indicated a BCC crystalline structure with a typical grain size of ≈3 nm. Hydrogen can be absorbed without activation procedures at high temperatures. Up to H/M ≈ 0.08, one can observe the occurrence of a solid solution of hydrogen in the alloy, while at a higher hydrogen content, the formation of a hydride is likely to occur. The maximum hydrogen content is H/M ≈ 0.4 at the maximum investigated pressure in this study of p ≈ 45 bar. Both the hydrogenation enthalpy and entropy decrease as the hydrogen content increases, and the shape of the sorption isotherms is different from that of V85Ni15 produced by induction melting, possibly because of the nanometric dimensions of the particles produced by ball milling.

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Section: Stoichiometric and Structural Analysissupporting

confidence: 88%

Section: Stoichiometric and Structural Analysismentioning

confidence: 74%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Mechanochemical Synthesis and Hydrogen Sorption Properties of a V-Ni Alloy

et al. 2022

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“…Regarding pure metals, the benchmarks of a normal and inverse isotope effect are vanadium and palladium, respectively [51]. Usually the occurrence of the same type of isotope effect is retained also in alloys of these metals [53,54]. The occurrence of the inverse isotope effect in Pd 77 Ag 23 here reported was perfectly in line with the occupancy of octahedral interstitial sites recently evidenced by means of neutron diffraction measurements [39,40].…”

Section: Hydrogen Isotope Effect In Pd 77 Ag 23supporting

confidence: 81%

Promising Isotope Effect in Pd77Ag23 for Hydrogen Separation

et al. 2021

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Pd–Ag alloys are largely used as hydrogen separation membranes and, as a consequence, the Pd–Ag–H system has been intensively studied. On the contrary, fewer information is available for the Pd–Ag–D system; thus, the aim of this work is to improve the knowledge of the isotope effect on the commercial Pd77Ag23 alloy, especially for temperature above 200 °C. In particular, deuterium absorption measurements are carried out in the Pd77Ag23 alloy in the temperature range between 79 and 400 °C and in the pressure range between 10−2 and 16 bar. In this exploited pressure (p) and composition (c) range, above 300 °C the pc isotherms display the typical shape of materials where only a solid solution of deuterium is present while at lower temperatures these curves seem to be better described by the coexistence of a solid solution and a deuteride in a large composition range. The obtained results are compared and discussed with the ones previously measured with the lightest hydrogen isotope. Such a comparison shows that the Pd77Ag23 alloy exhibits a clear inverse isotope effect, as the equilibrium pressure of the Pd–Ag–D system is higher than in Pd–Ag–H by a factor of ≈2 and the solubility of deuterium is about one half of that of hydrogen. In addition, the absorption measurements were used to assess the deuteration enthalpy that below 300 °C is ΔHdeut = 31.9 ± 0.3 kJ/mol, while for temperatures higher than 300 °C, ΔHdeut increases to 43 ± 1 kJ/mol. Additionally, in this case a comparison with the lighter isotope is given and both deuteration enthalpy values result lower than those reported for hydrogenation. The results described in this paper are of practical interest for applications operating above 200 °C, such as membranes or packing column, in which Pd77Ag23 has to interact with a gas stream containing both hydrogen isotopes.

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Efficient Thermal Processes Using Alternating Electromagnetic Field for Methodical and Selective Release of Hydrogen Isotopes

et al. 2021

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The controlled and selective release of hydrogen isotopes from lanthanum−nickel−aluminum (LANA) materials was achieved using an alternating electromagnetic field (AEMF). In the presence of the AEMF, the rate of desorption for D 2 was faster than for H 2 . In a closed system, compared to the control experiments with helium, hydrogen-loaded LANA samples showed a significant increase in pressure, which illustrate the desorption of hydrogen from the applied AEMF. An exponential increase in the hydrogen release rate was observed with an increased AEMF strength. Additionally, hydrogen release from LANA confined in a subzero environment (−78 °C) using an AEMF was demonstrated. These results demonstrate that the LANA material can be heated directly using alternating electromagnetic fields rather than indirectly to rapidly and selectively desorb hydrogen isotopes. The rapid response and difference in desorption kinetics for different hydrogen isotopes in the presence of the alternating electromagnetic fields provide a promising pathway for applications requiring the controlled release of hydrogen and separation of its isotopes.

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Deuterium absorption properties of V85Ni15 and evidence of isotope effect

Cited by 4 publications

References 26 publications

Mechanochemical Synthesis and Hydrogen Sorption Properties of a V-Ni Alloy

Mechanochemical Synthesis and Hydrogen Sorption Properties of a V-Ni Alloy

Promising Isotope Effect in Pd77Ag23 for Hydrogen Separation

Efficient Thermal Processes Using Alternating Electromagnetic Field for Methodical and Selective Release of Hydrogen Isotopes

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