Electrochemical Properties of Some Palladium Alloy Hydride Electrodes*

Sakamoto, Y.; Ishimaru, N.; Hasebe, M.

doi:10.1524/zpch.1994.183.part_1_2.319

Cited by 13 publications

(13 citation statements)

References 11 publications

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“…This effect is well pronounced for the alloys containing 80.9% Pd in the bulk, where at 298 K the maximum absorption capacity corresponds to H/M ratio of almost 0.55, while at 328 K it reaches only 0.30. These results are in line with other authors' reports on hydrogen absorption in Pd-Rh alloys both under gas phase and electrochemical conditions [5][6][7][8][9]. Thus, the absorption properties of Pd-Rh alloys are an exception to a general rule that Pd alloying with a non-absorbing element causes a deterioration of the hydrogen absorption capacity [2].…”

Section: Resultssupporting

confidence: 91%

“…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]. We have found that in the temperature range of 283-328 K the alloy which absorbs the largest amount of hydrogen consists of 92.6% of Pd in the bulk.…”

Section: Resultsmentioning

confidence: 80%

“…According to the band model the gaps in the Pd d-band are partially filled by the other metal's electrons and therefore less gaps remain for the electrons from absorbed hydrogen [2,4]. However, Pd-Rh alloys are an exceptional system in that the amount of absorbed hydrogen is larger (for Pd-rich alloys) than in case of pure Pd [5][6][7][8][9]. In the case of low Rh content there is an increase in the number of gaps in the Pd d-band below Pd Fermi level [4], which is manifested by an increase in the maximum amount of hydrogen absorbed in Pd-Rh alloys.…”

Section: Introductionmentioning

confidence: 99%

“…The literature gives different information about Rh bulk content in Pd-Rh alloys corresponding to the highest amount of absorbed hydrogen. Most literature data indicate that the highest ability to absorb hydrogen is exhibited by Pd-Rh alloys containing 2-10 at.% Rh in the bulk [5][6][7][8][9]. However, some results suggest that alloys containing even ca.…”

Section: Introductionmentioning

confidence: 99%

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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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Section: Resultssupporting

confidence: 91%

Section: Resultsmentioning

confidence: 80%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

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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“…Despite the crystal lattice expansion after Pd alloying with Pt, the Pt-Pd system behaves as a contracted alloy [1,3,4,10,13,21,27,30,31,37,43,48]. In the case of a PdRh alloy containing several percent of Rh the amount of hydrogen absorbed as the b-phase is greater than in pure Pd [7,9,11,13,25,30,32,38,40], although for pure Rh (as well as pure Pt [10]) the hydride formation 0022-0728/$ -see front matter Ó 2004 Elsevier B.V. All rights reserved. doi:10.1016/j.jelechem.2004.07.001 commences at hydrogen pressures much higher than for Pd [54].…”

Section: Introductionmentioning

confidence: 99%

Hydrogen electrosorption in Pd–Pt–Rh alloys

Łukaszewski¹,

Grdeń²,

Czerwiński³

2004

Journal of Electroanalytical Chemistry

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The process of hydrogen electrosorption in thin Pd-Pt-Rh alloys has been investigated mainly in acidic solution using cyclic voltammetry and chronoamperometry. The influence of electrode potential on the amount of electrosorbed hydrogen is presented. On the plot of H/M (hydrogen atoms/metal atoms) vs. potential the regions of pure a-and b-phase existence as well as the region of a-b phase transition can be distinguished. The maximum amount of absorbed hydrogen depends on the bulk composition being relatively high for Pd-rich alloys, although smaller than for pure Pd. The a-b transition is shifted to lower potentials in comparison with pure Pd. The process of phase transition seems to control the rate of hydrogen absorption and desorption into/from thin Pd-based electrodes. The hysteresis effect is observed in chronoamperometric absorption and desorption experiments. Potential cycling of PdPt-Rh alloys through the oxygen region leads to significant changes in hydrogen absorption properties with the appearance of an additional bulk phase.

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Thermodynamic Properties for Solution of Hydrogen in Palladium‐Based Binary Alloys

Sakamoto

Chen

Ura

et al. 1995

Ber Bunsenges Phys Chem

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The thermodynamic parameters for solution of hydrogen at infinite dilution and the (a+B) plateau thermodynamic properties for hydrogen absorption at moderate temperatures for a series of Pd‐based f.c.c binary alloys with relatively low solute metal content have been correlated from the viewpoint of whether the alloy lattice is expanded or contracted to parent Pd lattice. Newly determined data for Pd‐Zn, Pd‐Sb, Pd‐Bi, Pd‐Cr, Pd‐Mo and Pd‐Mn alloys are included. When alloys with solute metals in the same groups are compared, the lattice parameters of Pd binary alloys with the 4 d and 5 d transition elements are, in general, larger than those with the 3 d elements. The relative partial molar enthalpy, ΔH0H, at infinite dilution becomes more exothermic with an increase of lattice parameter for the lattice‐expanded alloys with the exception of Pd‐Pt alloys. Conversely, for contracted alloys, with the exceptions of Pd‐Li, Pd‐Zn, Pd‐Al and low Ti content Pd‐Ti alloys, the enthalpy becomes less exothermic with increasing lattice contraction. The dilute phase solubility at the same temperature as reflected by the relative chemical potential of dissolved hydrogen at infinite dilution, Δμ0H, increases with increasing lattice expansion for the expanded alloys, with the exceptions of Pd‐Pt and Pd‐Nb (Ta), whereas for the contracted alloys, the solubility decreases with increasing lattice contraction, with the exception of the Pd‐Li alloys. The standard free energy change, ΔG0plat' for B‐hydride formation in the expanded alloys decreases with increase of lattice expansion with the exceptions of the Pd‐Pt, Pd‐Zr, Pd‐Sb, Pd‐Nb(Ta) and Pd‐Mn alloys. For the contracted alloys, the B‐hydride becomes less stable with increasing lattice contraction except for the Pd‐Li alloys. The isobaric hydrogen solubilities in Pd alloys at relatively high pressures may be attributed to the influence of the solute metal atoms on the Pd band structure and to the exclusion of H from site occupation due to solute atoms in the nearest neighbor shells; both of these effects are independent of the lattice expansion and contraction.

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Electrochemical Properties of Some Palladium Alloy Hydride Electrodes*

Cited by 13 publications

References 11 publications

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

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

Hydrogen electrosorption in Pd–Pt–Rh alloys

Thermodynamic Properties for Solution of Hydrogen in Palladium‐Based Binary Alloys

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