Absorption of hydrogen isotopes by Pd–Pt alloys

Yasumatsu, Tatsuro; Wan, Jing; Matsuyama, Masao; Watanabe, Kuniaki

doi:10.1016/s0925-8388(99)00438-7

Cited by 28 publications

(34 citation statements)

References 6 publications

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“…This feature was the same as reported for other Pd alloys, 4,20,23,24) but magnitude of the isotope effect for the present alloy was slightly larger than that for palladium. 20) This suggests that the potential curve for hydrogen in the octahedral site, which is the site occupied by hydrogen in the present alloy, is slightly gentler than that of palladium. A gradual potential curve of the octahedral site generally gives rise to a large isotope effect on hydrogen absorption.…”

Section: Thermodynamic Propertysupporting

confidence: 73%

Thermodynamic and Magnetic Properties of Pd0.93Ag0.07 Hydride

et al. 2007

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Section: Thermodynamic Propertysupporting

confidence: 73%

Thermodynamic and Magnetic Properties of Pd0.93Ag0.07 Hydride

et al. 2007

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“…In regard to other types of alloys, e.g., Pd-Au [20,[36][37][38] or Pd-Pt [21,34,[39][40][41], the Pd-Rh system demonstrates a very unusual hydrogen absorption behavior. With the addition of a small amount of Rh the maximum alloy absorption capacity in the β phase increases [4][5][6][7][8][9].…”

Section: Resultsmentioning

confidence: 99%

Influence of rhodium additive on hydrogen electrosorption in palladium-rich Pd–Rh alloys

Koss

Łukaszewski

Hubkowska

et al. 2011

J Solid State Electrochem

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Hydrogen electrosorption into Pd-rich (>80 at.% Pd in the bulk) Pd-Rh alloys has been studied in acidic solutions (0.5 M H 2 SO 4 ) using cyclic voltammetry and chronoamperometry. The influence of temperature (in the range between 283 and 328 K), electrode potential and alloy bulk composition on hydrogen electrosorption properties of Pd-Rh alloys is presented. It has been found that the additive of Rh to Pd-Rh alloys increases the maximum hydrogen solubility (for Rh bulk content below 10 at.%), decreases the potential of absorbed hydrogen oxidation peak and decreases the potential of the α→β phase transition. Increasing temperature decreases the potential of absorbed hydrogen oxidation peak, the maximum hydrogen solubility, and the potential of the α→β phase transition. The amounts of electrosorbed hydrogen for α-and β-phase boundaries, i.e., α max and β min , have been determined from the integration of the initial parts of current-time responses in hydrogen absorption and desorption processes. The H/M ratio corresponding to α max increases with increasing Rh content, while for β min a maximum of H/M ratio is observed for the alloys containing ca. 95% Rh.

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“…[1][2][3] The property of Pd-Pt alloys is especially useful for the separation of hydrogen isotopes and has been successfully applied for an advanced gas chromatography for hydrogen isotope separation around room temperature without using any replacement gas. [4][5][6] It is reported in our previous papers 7,8) that the heat of hydrogen absorption as well as hydride formation decreases with increasing platinum-content in the alloy. On the other hand, the thermodynamic isotope effect on hydrogen absorption measured by the ratio of equilibrium pressures between protium and deuterium are almost invariable despite the change in the alloy composition.…”

Section: Introductionmentioning

confidence: 99%

“…On the other hand, the thermodynamic isotope effect on hydrogen absorption measured by the ratio of equilibrium pressures between protium and deuterium are almost invariable despite the change in the alloy composition. 7,8) It suggests that one can select a proper alloy for operation under a given condition of the chromatograph without changing the magnitude of the isotope effect. 7,8) From the other viewpoint, however, since the isotope separation by this system is principally due to the thermodynamic isotope effect, an important factor for separation is to establish absorption equilibrium in a separation column during flowing out of the charged mixture gas of hydrogen isotopes.…”

Section: Introductionmentioning

confidence: 99%

“…7,8) It suggests that one can select a proper alloy for operation under a given condition of the chromatograph without changing the magnitude of the isotope effect. 7,8) From the other viewpoint, however, since the isotope separation by this system is principally due to the thermodynamic isotope effect, an important factor for separation is to establish absorption equilibrium in a separation column during flowing out of the charged mixture gas of hydrogen isotopes. Therefore, it is required that the rates of absorption and desorption are sufficiently fast and the kinetic isotope effect does not affect the separation efficiency.…”

Section: Introductionmentioning

confidence: 99%

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Kinetics of Hydrogen Isotope Absorption for Well-Annealed Palladium-Platinum Alloys

et al. 2007

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Absorption kinetics of protium and deuterium for Pd, Pd-4 at%Pt and Pd-8 at%Pt were studied in a dilute hydrogen concentration region in a temperature region from 274 to 357 K by means of constant volume method, where samples were annealed well at 973 K under vacuum before measurements to remove defects induced by sample preparation. It was found that protium had larger rate constants for adsorption, lower rate constants for desorption and larger diffusion constants than those of deuterium within the examined temperature region. The activation energy of hydrogen absorption for both hydrogen isotopes was almost null for all of the samples used. The activation energy of desorption for deuterium was smaller than that for protium. It was attributed to the difference in the enthalpy of hydrogen absorption into metal in dilute hydrogen concentration region between protium and deuterium. These features and trends observed in the alloying effect were supported by the ab initio calculations for small clusters.

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Absorption of hydrogen isotopes by Pd–Pt alloys

Cited by 28 publications

References 6 publications

Thermodynamic and Magnetic Properties of Pd<SUB>0.93</SUB>Ag<SUB>0.07</SUB> Hydride

Thermodynamic and Magnetic Properties of Pd<SUB>0.93</SUB>Ag<SUB>0.07</SUB> Hydride

Influence of rhodium additive on hydrogen electrosorption in palladium-rich Pd–Rh alloys

Kinetics of Hydrogen Isotope Absorption for Well-Annealed Palladium-Platinum Alloys

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