A study of melting of various types of Pt–Pd nanoparticles

Чепкасов, И. В.; Gafner, Yu. Ya.; Vysotin, M. A.; Redel, L. V.

doi:10.1134/s1063783417100109

Cited by 23 publications

(10 citation statements)

References 19 publications

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“…Nevertheless, Pd atoms diffuse actively to the surface after the melting and decrease the potential energy. The process of PtPd NPs melting was described in detail in our recent work …”

Section: Resultsmentioning

confidence: 99%

“…The process of PtPd NPs melting was described in detail in our recent work. 64 To investigate the influence of the NP structure on its electron density distribution, a series of DFT calculations were performed using OpenMX software followed by the Bader charge analysis. 52 Figure 5 shows the dependences of average surface charge on the Pt percentage for three different NPs structures.…”

Section: Resultsmentioning

confidence: 99%

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Stability and Electronic Properties of PtPd Nanoparticles via MD and DFT Calculations

et al. 2018

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The structural as well as electronic properties of PtPd nanoparticles (NPs) were investigated by using molecular dynamics simulations and density functional theory calculations. A wide range of NPs of different sizes (from 1.5 to 4 nm), structures (core−shell, alloy, Janus), and compositions were taken into consideration. It was shown that PtPd NPs of less than ∼2.0 nm are prone to structural transformations to icosahedral (Ih) shape, regardless of their initial structure and composition. On the other hand, for NPs of size ∼2.5 nm, the increase of temperature up to 700−900 K leads to structural changes only for compositions close to 40% Pt, which corresponds to energetic minimum for Pt@Pd NPs. The Ih form of Pd@Pt NPs with monolayer thickness of Pt on the surface appears to have the most negatively charged surface which makes this kind of NPs the best candidate for catalysis application.

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“…Nevertheless, Pd atoms diffuse actively to the surface after the melting and decrease the potential energy. The process of PtPd NPs melting was described in detail in our recent work …”

Section: Resultsmentioning

confidence: 99%

Section: Resultsmentioning

confidence: 99%

Stability and Electronic Properties of PtPd Nanoparticles via MD and DFT Calculations

et al. 2018

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“…Apparently Zhang et al [33] were the first who noticed such a step change in the caloric curve and attributed it to a solid-state transition using CNA. Utilization of heat capacity has been also demonstrated for a more complex transition at elevated temperature in Pt-Pd alloy [34,35]. In this case, a visible change in the nanoparticle shape and number of surface…”

Section: Relaxationmentioning

confidence: 92%

Determining phase transition using potential energy distribution and surface energy of Pd nanoparticles

Azadeh

Kateb

Marashi

2019

Computational Materials Science

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Molecular dynamics simulation is employed to understand the thermodynamic behavior of cuboctahedron (cub) and icosahedron (ico) nanoparticles with 2 -20 number of shells (55 -28741 atoms). The embedded atom method was used to describe the interatomic potential. Conventional melting criteria such as potential energy and specific heat capacity (C p ) caloric curves as well as structure analysis by radial distribution function (G(r)) and common neighbor analysis (CNA) were utilized simultaneously to provide a comprehensive picture of the melting process. It is shown that the potential energy distribution and surface energy (γ p ) proposed here are holding several advantages over previous criteria. In particular, potential energy distribution can distinguish between interior and surface atoms and even corner, edge and plane atoms at the surface. While G(r) and CNA are not surface sensitive methods and cannot distinguish between surface melting and an allotropic transition. It is also shown that allotropic change appears more clearly in C p and γ p rather than potential energy. However, determining accurate C p requires enough sampling to be averaged. Finally, a few issues in the current methods for determining γ p were discussed and a simple method based on available models was proposed which, independent of estimation of the surface area, predicts the correct temperature and size-dependent trend in agreement with Guggenheim-Katayama and Tolman's models, respectively.

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“…To simulate a particle in a vacuum and a matrix of another metal, a model similar to the models in [13,18] was used. The particle was created in the model by cutting out a ball of the corresponding size from an ideal crystal.…”

Section: Description Of the Modelmentioning

confidence: 99%

“…The temperature in the model was set through the initial velocities of the atoms according to the Maxwell-Boltzmann distribution, wherein the thermal expansion of the calculation blocks was taken into account [19 -22]. Due to the fact that at high temperatures diffusion at the Ti-Al interface proceeds actively and the boundary is rapidly blurred, the method of searching for the melting temperature by gradually increasing the temperature, as in [12,13], was excluded. In our work, we began each experiment with a starting structure, setting one or another temperature, keeping it constant using a Nose-Hoover thermostat.…”

Section: Description Of the Modelmentioning

confidence: 99%

Melting temperature of Ti and TiAl nanoparticles in vacuum and in Al matrix depending on their diameter: molecular dynamics study

2021

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The dependence of the melting temperature of Ti and TiAl nanoparticles on their diameter in vacuum and in Al matrix was studied by the method of molecular dynamics using EAM potentials of Zope and Mishin. Particles with a diameter of 2.5 to 12 nm were considered. The obtained values of the melting point are in good agreement with the approximation curves constructed on the basis that the decrease in the melting temperature is proportional to the ratio of the surface area of the particle to its volume. Wherein the values of the melting temperature of Ti and TiAl particles in the aluminum matrix turned out to be lower than those of particles in vacuum, which is explained by the smearing and disordering of the interface due to mutual diffusion. As the size of particles in vacuum and in aluminum increased, the values of their melting points tended to the same value, which is explained by the decrease in the role of the diffusion-blurred interface with an increase in the particle diameter. The particles began to melt from the surface. The velocity of movement of the melting front depended on temperature and increased with increasing temperature. In the case of particles in aluminum matrix, at temperatures close to the particle melting point, mutual diffusion was significantly accelerated due to melting of the particle boundary layer. Al atoms penetrating into the particle accelerated the movement of the melting front, rapidly occupying the next destroyed layer of the particle.

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A study of melting of various types of Pt–Pd nanoparticles

Cited by 23 publications

References 19 publications

Stability and Electronic Properties of PtPd Nanoparticles via MD and DFT Calculations

Stability and Electronic Properties of PtPd Nanoparticles via MD and DFT Calculations

Determining phase transition using potential energy distribution and surface energy of Pd nanoparticles

Melting temperature of Ti and TiAl nanoparticles in vacuum and in Al matrix depending on their diameter: molecular dynamics study

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