Evolution of Carbon Nanofiber-Supported Pt Nanoparticles of Different Particle Sizes: A Molecular Dynamics Study

Cheng, Hongye; Zhu, Yi‐An; Chen, De; Åstrand, Per‐Olof; Li, Ping; Qi, Zhiwen; Zhou, Xiaohai

doi:10.1021/jp505554w

Cited by 20 publications

(26 citation statements)

References 57 publications

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“…Although both cluster sizes show NTE, the onset of contraction occurs at ∼300 K for Pt 10 and ∼400 K for Pt 20 , showing a similar behavior to other simulations 15. Moreover, while the…”

supporting

confidence: 84%

Molecular Dynamics Simulations of Supported Pt Nanoparticles with a Hybrid Sutton–Chen Potential

et al. 2016

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Understanding the physical and chemical behavior of supported nanoscale catalysts is of fundamental and technological importance. However, their behavior remains poorly understood, in part due to their complex, dynamical structure, and the nature of interactions at the nanoscale. We found previously that real-time ab initio finite temperature DFT simulations provide fundamental insights into the dynamic and electronic structure of nanoparticles. Unfortunately, such first-principles calculations are very computationally intensive. To make such simulations more feasible, we have developed a hybrid version of the classical Sutton-Chen model potential which is orders of magnitude more efficient. This potential is parametrized to previous DFT/MD simulations, and accounts for many-body effects induced by the support. The model is applied to Pt 10,20 nanoparticles supported on a model γ-Al 2 O 3 surface. In addition to the thermal variation of the internal structure, the model also predicts diffusion coefficients and bond-breaking rates. The simulations reveal size-dependent dynamical changes with increasing temperature, as the clusters go from a "frozen" state attached to the support, to a "liquid" state where they are free to diffuse. These changes provide a rationale for the observed negative thermal expansion. Implications for nanoscale catalysis are briefly discussed.

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confidence: 84%

Molecular Dynamics Simulations of Supported Pt Nanoparticles with a Hybrid Sutton–Chen Potential

et al. 2016

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“…This largely amorphous substrate, with regions of graphitic planes, is excluded due to the difficulty in modelling it. Carbon supports have been shown to interact rather weakly with platinum nanoparticles [32,33], and there is some evidence that the effect on the morphology of nanoparticles with diameters similar to those studied here is not large [34].…”

Section: Resultssupporting

confidence: 50%

Ideal versus real: simulated annealing of experimentally derived and geometric platinum nanoparticles

Ellaby¹,

Aarons²,

Varambhia³

et al. 2018

J. Phys.: Condens. Matter

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Platinum nanoparticles find significant use as catalysts in industrial applications such as fuel cells. Research into their design has focussed heavily on nanoparticle size and shape as they greatly influence activity. Using high throughput, high precision electron microscopy, the structures of commercially available Pt catalysts have been determined, and we have used classical and quantum atomistic simulations to examine and compare them with geometric cuboctahedral and truncated octahedral structures. A simulated annealing procedure was used both to explore the potential energy surface at different temperatures, and also to assess the effect on catalytic activity that annealing would have on nanoparticles with different geometries and sizes. The differences in response to annealing between the real and geometric nanoparticles are discussed in terms of thermal stability, coordination number and the proportion of optimal binding sites on the surface of the nanoparticles. We find that annealing both experimental and geometric nanoparticles results in structures that appear similar in shape and predicted activity, using oxygen adsorption as a measure. Annealing is predicted to increase the catalytic activity in all cases except the truncated octahedra, where it has the opposite effect. As our simulations have been performed with a classical force field, we also assess its suitability to describe the potential energy of such nanoparticles by comparing with large scale density functional theory calculations.

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“…413 Simulations have shown that upon adsorption, the distribution of first-shell Pt-Pt coordination number changes significantly for Pt NP up to 2 nm, and that the restructuration of the NP decreases with particle size (Figure 20). 414 This was attributed both to the reduced binding energy per Pt atom bonded to the support and to the increased cohesive energy of the Pt NP. According to the orientation of graphene sheets, CNF are classified into three categories, platelet type, tubular type, and fishbone (or herringbone) type CNF, with their graphene sheets perpendicular, parallel, and tilted to the principal axis, respectively.…”

Section: Geometric Effectsmentioning

confidence: 99%

A Theory/Experience Description of Support Effects in Carbon-Supported Catalysts

2019

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Fermi level in vii) are shown in purple in ii)-vi) with an iso-value of ±0.003 a.u. Reprinted with permission from ref 57 . Copyright 2014 from the Royal Society of Chemistry; b) Molecular model of a corannulene-like element functionalized with three carboxylic groups from two different perspectives in the cpk representation (on the left). The final structure (190 elements in a cubic cell of 60 Å in size) obtained from random packing of the individual elements (on the right). Cyan: carbon, red: oxygen, white: hydrogen. Reprinted with permission from ref 59 Copyright 2017 from Elsevier; c) Side-views of Ru13 adsorbed on Gr-DV-2COOH site before (on left panel) and after a proton jump (right panel). C atoms are in black, O in red, H in with white and Ru in mocha. Reprinted with permission from ref 60 Copyright 2014 from Elsevier; and d) Spin-density projection in µB/a.u. 2 on the graphene plane around i) the hydrogen chemisorption defect (∆) and ii) the vacancy defect in the a sublattice. Carbon atoms corresponding to the a sublattice (o) and to the b sublattice (•) are distinguished. Simulated STM images of the defects are shown in iii) and iv), respectively. Reprinted with permission from ref 61 .

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Evolution of Carbon Nanofiber-Supported Pt Nanoparticles of Different Particle Sizes: A Molecular Dynamics Study

Cited by 20 publications

References 57 publications

Molecular Dynamics Simulations of Supported Pt Nanoparticles with a Hybrid Sutton–Chen Potential

Molecular Dynamics Simulations of Supported Pt Nanoparticles with a Hybrid Sutton–Chen Potential

Ideal versus real: simulated annealing of experimentally derived and geometric platinum nanoparticles

A Theory/Experience Description of Support Effects in Carbon-Supported Catalysts

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