Interdiffusion study in the Pd–Pt system

Baheti, Varun A.; Ramesh, R.; Paul, Aloke

doi:10.1007/s10854-013-1179-1

Cited by 11 publications

(15 citation statements)

References 30 publications

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“…This effect can be attributed to the implicit composition-dependence of the diffusion coefficient which cannot be captured with the Fourier series solution according to equation (1). However, the trend shown here can be compared qualitatively to the results obtained by Baheti et al (2013) who explicitly determined the composition-dependence of the interdiffusion coefficient for PtPd diffusion couples using electron probe micro-analyzer (EPMA), annealed at elevated temperatures of 1,423–1,573 K, though. They found that the diffusivities are the highest for both pure compositions, but reach a practically steady value for intermediate compositions.…”

Section: Discussionsupporting

confidence: 80%

Probing the Miscibility Gap of the Pt–Pd Binary System by Atom Probe Tomography

Lee

Stender

Eich

et al. 2022

Microscopy and Microanalysis

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To solve the uncertainty of the platinum (Pt)–palladium (Pd) phase diagram, especially the existence of a suggested miscibility gap, atom probe tomography (APT) was used to determine the time evolution of the composition after heat treatment. Due to the extraordinarily slow diffusion in the temperature range of the controversial phase separation, the investigated volume was limited to nano-sized multiple layers deposited by ion beam sputtering (IBS). The evaporated volume was reconstructed from the obtained datasets and the respective diffusion coefficients were determined using the Fourier series solution of the diffusion equation. Beginning with pure Pt and Pd layers annealed at 673, 773, 873, and 973 K, the mixing appears to be purely diffusion controlled in the chosen annealing times, but the state of complete mixing was still not observed. Therefore, extended isothermal annealing sequences at 673 and 773 K with pre-alloyed layers have been carried out. They clearly suggest complete mixing even at the lowest investigated temperatures.

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Section: Discussionsupporting

confidence: 80%

Probing the Miscibility Gap of the Pt–Pd Binary System by Atom Probe Tomography

Lee

Stender

Eich

et al. 2022

Microscopy and Microanalysis

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“…We examined a number of processes (such as one-to-one atom exchange, as well as three-body and four-body rotations), and concluded that (i) diffusion of Pd and Pt atoms through Pt, at 100°C, must be vacancymediated, and (ii) the lowest diffusion barrier is for Pd through Pt (0.88 eV). Previous experimental studies of Pd-Pt interdiffusion also found that Pd had a higher diffusion rate in Pt than in Pd (21).…”

mentioning

confidence: 81%

Platinum-based nanocages with subnanometer-thick walls and well-defined, controllable facets

Zhang

Roling

Wang

et al. 2015

Science

904

786

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A cost-effective catalyst should have a high dispersion of the active atoms, together with a controllable surface structure for the optimization of activity, selectivity, or both. We fabricated nanocages by depositing a few atomic layers of platinum (Pt) as conformal shells on palladium (Pd) nanocrystals with well-defined facets and then etching away the Pd templates. Density functional theory calculations suggest that the etching is initiated via a mechanism that involves the formation of vacancies through the removal of Pd atoms incorporated into the outermost layer during the deposition of Pt. With the use of Pd nanoscale cubes and octahedra as templates, we obtained Pt cubic and octahedral nanocages enclosed by {100} and {111} facets, respectively, which exhibited distinctive catalytic activities toward oxygen reduction.

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“…The large concentration of vacancies may agglomerate and form voids known as Kirkendall voids, which acts as a sink for vacancies [61]. The Kirkendall effect is common in interdiffusion systems, even with a difference in diffusion coefficient of only 1-2 orders of magnitude, as in the Pd-Pt system [62]. The oxidation of Ni to NiO is also influenced by the Kirkendall effect.…”

Section: Diffusionmentioning

confidence: 99%