Enthalpies of formation of liquid and solid (gallium + palladium) alloys

Allam, D. El; Gaune‐Escard, M.; Bros, J.P.; Hayer, E.

doi:10.1007/bf02654034

Cited by 27 publications

(5 citation statements)

References 4 publications

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“…A particularly interesting system for in‐depth interface studies of multimetallic catalytic interfaces is the Ga–Pd system. For this system negative mixing enthalpies are reported for the whole composition range, and a pronounced tendency for ordering is manifested through multiple IMCs (Ga/Pd <5) distributed over the whole phase diagram . These IMCs are high melting and are present in the form of solid nanoparticles.…”

Section: Introductionmentioning

confidence: 94%

“…For this system negative mixing enthalpies are reportedf or the whole composition range, and ap ronouncedt endency for ordering is manifested through multiple IMCs (Ga/Pd < 5) distributed over the whole phase diagram. [5,6] These IMCs are high meltinga nd are present in the form of solid nanoparticles. These Pd-rich IMCs have been applied by several groups,f or example, for methanol steam reforming, [7][8][9][10][11] hydrogenation of alkynes, [12][13][14] or dehydrogenation of alkanes.…”

Section: Introductionmentioning

confidence: 99%

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Spectroscopic Observation and Molecular Dynamics Simulation of Ga Surface Segregation in Liquid Pd–Ga Alloys

Grabau

Erhard

Taccardi

et al. 2017

Chemistry A European J

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Liquid binary Pd-Ga alloys with low Pd contents of 0.8, 1.8, and 4.7 at % of Pd were examined as a function of sample temperature in ultra-high vacuum by using angle-resolved XPS. Upon cooling from 750 to 400 K, a pronounced temperature-dependence of the Pd concentration in the liquid phase was observed, which was explained by the transition from the pure liquid phase to a two-phase system, consisting of a solid Ga Pd phase and a Pd-depleted liquid Pd-Ga alloy. In the liquid Pd-Ga alloy, Pd is always depleted from the topmost interface layer, as deduced from angle-resolved XPS at 0 and 80° emission, independent of temperature and Pd concentration. This observation is interpreted as an inhomogeneous depth distribution function of Pd, that is, the segregation of Ga to the surface of the liquid phase. The results of a DFT-based molecular dynamics simulation (MD) independently show interfacial stratification of Ga and an inhomogeneous Pd distribution along the surface normal. The evaluation of the experimental data with a rigid layer model based on the MD calculations leads to excellent agreement with the simulation.

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Section: Introductionmentioning

confidence: 94%

Section: Introductionmentioning

confidence: 99%

Spectroscopic Observation and Molecular Dynamics Simulation of Ga Surface Segregation in Liquid Pd–Ga Alloys

Grabau

Erhard

Taccardi

et al. 2017

Chemistry A European J

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“…Each Pd atom is therefore surrounded by 7 Ga atoms (3 + 3 + 1) [14] . Thermodynamically, the formation of stable intermetallic compounds can be explained on the basis of considerable enthalpies of formation [15] . The energetically favorable Pd–Ga interaction can be understood on the basis of strong, localized and covalent Pd–Ga bonds [16] .…”

Section: Introductionmentioning

confidence: 99%

In situ XPS study of methanol reforming on PdGa near-surface intermetallic phases

Rameshan

Stadlmayr

Penner

et al. 2012

Journal of Catalysis

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Graphical abstractHighlights► A Pd1Ga1 surface without Ga2O3 contact is inactive for CO2 formation in methanol steam reforming. ► In situ XPS spectroscopy showed that water activation is blocked on Pd1Ga1. ► The valence band electronic structure of Pd1Ga1 favors selective dehydrogenation to H2CO. ► In oxidative steam reforming, the Pd1Ga1 surface behaves like extended Pd. ► Thus, total methanol oxidation by O2 at low temperatures is predominant.

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“…Figure 3 shows the calculated temperature-independent enthalpy of mixing of the liquid phase, in good agreement enthalpy of mixing of Pd in liquid In was calculated and plotted in Figure 4 together with the measured limiting parwith experimental measurements at various temperatures. The two data points from Allam et al's [18] measurements tial molar enthalpy-of-mixing data. The agreement is quite good, even though none of those data were used in the at 1592 K, with the composition of 63.85 at.…”

Section: Thermodynamic Modelingmentioning

confidence: 99%

Thermodynamic modeling of the indium-palladium system

Jiang

Liu

2002

Metall Mater Trans A

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The thermochemical and phase-equilibrium data of the In-Pd binary system were critically reviewed. A self-consistent thermodynamic description of the system was obtained using the CALPHAD approach. Eight intermetallic compounds were considered in the system. The InPd(B2) compound was described by a two-sublattice model. The compounds In 7 Pd 3 , In 3 Pd 2 , In 3 Pd 5 , ␣InPd 2 , and ␣InPd 3 , with negligible homogeneity ranges, were modeled as stoichiometric compounds. ␤InPd 2 and ␤InPd 3 were treated as stoichiometric compounds due to a lack of experimental information. Model calculations agreed satisfactorily with most existing experimental data. The thermodynamic factor for the InPd(B2) compound was also predicted based on the present thermodynamic description.

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Enthalpies of formation of liquid and solid (gallium + palladium) alloys

Cited by 27 publications

References 4 publications

Spectroscopic Observation and Molecular Dynamics Simulation of Ga Surface Segregation in Liquid Pd–Ga Alloys

Spectroscopic Observation and Molecular Dynamics Simulation of Ga Surface Segregation in Liquid Pd–Ga Alloys

In situ XPS study of methanol reforming on PdGa near-surface intermetallic phases

Thermodynamic modeling of the indium-palladium system

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