Thermodynamic and Magnetic Properties of Pd&lt;SUB&gt;0.93&lt;/SUB&gt;Ag&lt;SUB&gt;0.07&lt;/SUB&gt; Hydride

Hara, Masanori; Sakurai, Junichi; Akamaru, Satoshi; Hashizume, Kiyomi; Nishimura, K.; Okabe, Tetsuro; Watanabe, Kuniaki; Matsuyama, Masao

doi:10.2320/matertrans.mra2007150

Cited by 18 publications

(9 citation statements)

References 25 publications

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“…We want to point out that, to the best of our knowledge, no previous investigation of the absorption of deuterium in Pd-Ag alloys is available above 200 • C. Indeed, the previous reports about the hydrogen isotope effect in Pd-Ag alloys concerned Pd 93 Ag 7 [37] (100 • C < T < 200 • C) and Pd 77 Ag 23 [38] (101 • C < T < 146 • C), both samples investigated in the deuteride form. Anand reported a factor of three between the equilibrium pressure for deuterium compared to hydrogen for a composition of about 0.2 [37]. For a similar composition, in the case of the dehydrogenation of Pd 77 Ag 23 , a factor between two and three was reported for the ratio between the equilibrium pressure of deuterium and hydrogen [38].…”

Section: Hydrogen Isotope Effect In Pd 77 Ag 23mentioning

confidence: 92%

“…Pure palladium forms hydrides or deuterides below 290 and 283 • C, respectively [48,49], while above these temperatures only a solid solution can be observed. Some pressure-composition curves for Pd 93 Ag 7 [37] between 100 and 200 • C and for Pd 77 Ag 23 [38] between 101 and 146 • C displayed the typical shape for the formation of a deuteride. Further studies at higher temperatures are not available.…”

Section: Deuterium Absorption In Pd77ag23mentioning

confidence: 94%

“…A limited number of previous studies of the isotope effect in Pd-Ag alloys is available in a restricted temperature range for Pd 93 Ag 7 [37] (100 • C < T < 200 • C) and for Pd 77 Ag 23 [38] (101 • C < T < 146 • C). These results evidenced that the absorption properties of deuterium are different from those of hydrogen, concerning the equilibrium pressure between the gas and the solid and the solubility of the hydrogen isotopes.…”

Section: Introductionmentioning

confidence: 99%

“…Moreover, the occurrence of an isotope effect between hydrogen and deuterium, as suggested by the studies of Hara et al [37] and Anand et al [38], is the prerequisite to obtain a different concentration of the hydrogen isotopes in the gas emitted by the reactor for hydrogen purification, due to the possible different values of diffusion coefficient and solubility of the isotope in the metal (see Equation (1)). Additionally, in this respect, it is interesting to evidence the possible differences between the two hydrogen isotopes regarding their solubility in the Pd 77 Ag 23 alloy.…”

Section: Introductionmentioning

confidence: 99%

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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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Section: Hydrogen Isotope Effect In Pd 77 Ag 23mentioning

confidence: 92%

Section: Deuterium Absorption In Pd77ag23mentioning

confidence: 94%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Promising Isotope Effect in Pd77Ag23 for Hydrogen Separation

et al. 2021

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“…However, the magnetic susceptibility of Pd is very small [3], and can barely be quantified. Recently, the magnetic susceptibilities of Pd alloys have been reported as a function of the hydrogen concentration in bulk [5][6][7][8][9]. In these Pd alloys, the Pd-Co alloys with Co concentrations above 8 atom% exhibited ferromagnetic behavior [10] and the magnetic susceptibility decreased significantly with the hydrogen concentration in the bulk [9].…”

Section: Introductionmentioning

confidence: 97%