CO Adsorption-Induced Surface Segregation and Formation of Pd Chains on AuPd(100) Alloy: Density Functional Theory Based Ising Model and Monte Carlo Simulations

Zhu, Beien; Creuze, Jérôme; Mottet, C.; Legrand, Bernard; Guesmi, Hazar

doi:10.1021/acs.jpcc.5b10158

Cited by 31 publications

(41 citation statements)

References 41 publications

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“…At these compositions, the random-alloy approximation is thus acceptable at T > 250 K. This conclusion is supported by Ref. [23] (see also [22]) indicating that the descriptor, Pd-Au BOND , characterizing the difference of the Pd-Pd, Pd-Au, and Au-Au interactions, is fairly small, −20 meV ( Table 1 in [23]).…”

Section: Structure Of the Pd-au Alloysupporting

confidence: 52%

“…DFT-based calculations [area (iv)] are executed with periodic cells [20][21][22] or at the level of NPs containing ∼100 atoms [23]. A few ordered arrangements were predicted at various values of f [20].…”

Section: Structure Of the Pd-au Alloymentioning

confidence: 99%

“…(ii) For pure Au, DFT is in favor of H absorption on the T sites, whereas the H location in the O sites is predicted to be unstable [13,19]. (iii) For a Pd-Au alloy, the theory was used to scrutinize the arrangement of atoms [20][21][22][23][24]. In addition, DFT indicates that hydrogen absorption becomes less favorable with increasing Au content [25,26].…”

Section: Introductionmentioning

confidence: 99%

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Suppression of hysteresis in absorption of hydrogen by a Pd-Au alloy

Mamatkulov

Zhdanov

2020

Phys. Rev. E

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Hydrogen absorption by Pd exhibits hysteresis loops (provided the temperature is not too high) and represents one of the classical examples of first-order phase transitions in metals. Experiments indicate that addition of even a small amount of Au is able to suppress hysteresis. From this perspective, we analyze the energetics of hydrogen in a Pd-Au alloy by using extensive density-functional-theory (DFT) calculations. The dependence of the hydrogen binding energy on the number (n) of Au atoms forming an adsorption site is found to be appreciably nonlinear. With the DFT input for statistical calculations, we reproduce special features of the hydrogen absorption isotherms and explain the rapid decrease of the corresponding critical temperature with increasing Au fraction. The key factor here is that the phase transition is related primarily to absorption in sites formed only by Pd. With increasing Au amount, the fraction of such sites rapidly decreases, the distance between H atoms located there becomes on average larger, the interaction between them becomes weaker, and accordingly the driving force for the phase transition decreases. It is of interest that all these effects can be illustrated by taking only the configurations with n 2 into account. This means that in the context under consideration the fine details of the dependence of the hydrogen binding energy on n are in fact not too important.

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Section: Structure Of the Pd-au Alloysupporting

confidence: 52%

Section: Structure Of the Pd-au Alloymentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Suppression of hysteresis in absorption of hydrogen by a Pd-Au alloy

Mamatkulov

Zhdanov

2020

Phys. Rev. E

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“…Hence, an improvement of the electrocatalytic properties is required. Bimetallic materials have been explored to tune the chemical properties of the electrocatalysts to modify their activity for the reaction [13,14,15,16,17,18]. In this context, Cu seems an interesting choice to combine with Ni due to costs, corrosion stability in alkaline electrolytes and a weaker hydrogen adsorption (respect with Ni) [19].…”

Section: Introductionmentioning

confidence: 99%

Understanding the structure and reactivity of NiCu nanoparticles: an atomistic model

Quaino

Belletti

Shermukhamedov

et al. 2017

Phys. Chem. Chem. Phys.

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The structure of bimetallic NiCu nanoparticles (NP) is investigated as a function of their composition and size by means of Lattice MonteCarlo (LMC) and molecular dynamics (MD) simulations. According to our results, copper segregation takes place at any composition of the particles. We found that this feature is not size-dependent. In contrast, nickel segregation depends on the NP size. When the size increases, Ni atoms tend to remain in the vicinity of the surface and deeper. For smaller NPs, Ni atoms are located at the surface as well. Our results also showed that most of the metal atoms segregated at the surface area were found to decorate edges and/or form islands. Our findings agree qualitatively with the experimental data found in the literature. In addition, we comment on the reactivity of these nanoparticles.

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“…Therefore, cheap energy evaluations based on simplified Hamiltonians are often applied. [64][65][66] . Furthermore, if the model Hamiltonian captures the essential physics, it can also be used to gain insight into the driving force of the alloy formation.…”

Section: Application To Au Np Energy Fittingmentioning

confidence: 99%

Parameter-free coordination numbers for solutions and interfaces

Staub

Steinmann

2020

The Journal of Chemical Physics

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Coordination numbers are among the central quantities to describe the local environment of atoms and are thus used in various applications such as structure analysis, fingerprints and parameters. Yet, there is no consensus regarding a practical algorithm, and many proposed methods are designed for specific systems. In this work, we propose a scale-free and parameter-free algorithm for nearest neighbor identification. This algorithm extends the powerful Solid-Angle based Nearest-Neighbor (SANN) framework to explicitly include local anisotropy. As such, our Anisotropically corrected Solid-Angle based Nearest-Neighbor (ASANN) algorithm provides with a fast, robust and adaptive method for computing coordination numbers. The ASANN algorithm is applied to flat and corrugated metallic surfaces to demonstrate that the expected coordination numbers are retrieved without the need for any system-specific adjustments. The same applies to the description of the coordination numbers of metal atoms in AuCu nano-particles and we show that ASANN based coordination numbers are well adapted for automatically counting neighbors and the establishment of cluster expansions. Analysis of classical molecular dynamics simulations of an electrified graphite electrode reveals a strong link between the coordination number of Cs + ions and their position within the double layer, a relation that is absent for Na + , which keeps its first solvation shell even close to the electrode.

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CO Adsorption-Induced Surface Segregation and Formation of Pd Chains on AuPd(100) Alloy: Density Functional Theory Based Ising Model and Monte Carlo Simulations

Abstract: International audienc

Cited by 31 publications

References 41 publications

Suppression of hysteresis in absorption of hydrogen by a Pd-Au alloy

Suppression of hysteresis in absorption of hydrogen by a Pd-Au alloy

Understanding the structure and reactivity of NiCu nanoparticles: an atomistic model

Parameter-free coordination numbers for solutions and interfaces

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