Molecular dynamics studies of a model polymer–catalyst–carbon interface

Lamas, Eduardo J.; Balbuena, Perla B.

doi:10.1016/j.electacta.2006.03.033

Cited by 51 publications

(41 citation statements)

References 25 publications

(33 reference statements)

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“…For instance MD simulations are capable of addressing the catalytic material degradation (dissolution, Ostwald ripening, aggregation, detachment, etc.) in close connection to the experiment [87][88][89][90][91]. …”

Section: Future Perspectivesmentioning

confidence: 82%

Molecular dynamics simulations of supported metal nanocatalyst formation by plasma sputtering

Brault

Neyts

2015

Catalysis Today

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a b s t r a c tMagnetron sputtering is a widely used physical vapor deposition technique for deposition and formation of nanocatalyst thin films and clusters. Nevertheless, so far only few studies investigated this formation process at the fundamental level. We here review atomic scale molecular dynamics simulations aimed at elucidating the nanocatalyst growth process through magnetron sputtering. We first introduce the basic magnetron sputtering background and machinery of molecular dynamics simulations, and then describe the studies conducted in this field so far. We also present a perspective view on how the field may be developed further.

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Section: Future Perspectivesmentioning

confidence: 82%

Molecular dynamics simulations of supported metal nanocatalyst formation by plasma sputtering

Brault

Neyts

2015

Catalysis Today

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“…1 Most experimental and simulation studies of PEM are related to Nafion and other perfluorosulfonate polymers. Recent theoretical and simulation works made a significant progress in ͑1͒ the development of molecular force fields for Nafion backbone and sidechain, 2-4 ͑2͒ ab initio and density functional theory ͑DFT͒ modeling of Nafion sidechain and its interactions with water, [5][6][7][8][9] ͑3͒ molecular mechanics and molecular dynamics ͑MD͒ atomistic modeling of the solvation of Nafion sidechains and polymer fragments in various solvents, such as water, methanol, water-methanol mixture, and nerve agent simulant dimethylmethylphosphonate ͑DMMP͒, 5,10 ͑4͒ MD simulations of nanoscale segregation and diffusion in hydrated Nafion membranes, 4,9,[11][12][13][14][15][16][17][18][19][20][21][22][23][24][25][26][27][28] ͑5͒ modeling of the diffusion of water and ions in the vicinity of water-ionomer interfaces, 27,[29][30][31] ͑6͒ the development of semiempirical models of proton conduction 14,15,[26][27][28]32 ͑for reviews, see Refs. 33 and 34͒, and ͑7͒ the development of various regular and random network models.…”

Section: Introductionmentioning

confidence: 99%

Specifics of solvation of sulfonated polyelectrolytes in water, dimethylmethylphosphonate, and their mixture: A molecular simulation study

Vishnyakov

Neimark

2008

The Journal of Chemical Physics

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Sulfonated polyelectrolyte membranes (PEMs), such as Nafion and styrene-olefin block copolymers, are explored as permselective membranes for fuel cells as well as suitable barrier materials against chemical agents. The permselective properties of PEM are determined by their microphase segregation into hydrophilic and hydrophobic domains. We performed classical molecular dynamics simulations of solvation of the hydrophilic fragments of PEM exemplified on sulfonated polystyrene (sPS) with potassium, calcium, and aluminum as counterions, in water, phosphor-organic nerve agent simulant dimethylmethylphosphonate (DMMP), and their binary mixture. The force field for the sulfonate group has been developed by optimizing the potential parameters to fit the benzenesulfonate conformations obtained from the density functional theory. For a comparison, we considered perfluorosulfonate oligomers representing fragments of Nafion polymer. We found a noticeable difference between the geometries of the polymer backbone in different solvents. The polymer backbone is stiffer in DMMP for both sPS and Nafion. An anisotropic structuring of the solvent around the phenylsulfonate group is substantially stronger than around the Nafion sidechain due to the rigidity and the anisotropy of the phenylsulfonate group. The counterion significantly affects the conformations of solvated sPS: the rigidity of the backbone increases when potassium or calcium ions are replaced by trivalent aluminum ions.

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“…All interaction forces in the simulation are calculated according to the force field, therefore, the choice of an appropriate force field is critical. The DREIDING force filed [28] has been applied to study the dynamic and transport properties of the bulk membranes, yielding satisfactory results in several previous work [11,[13][14][15][16]19].We employ this force field in order to describe most of the inter-and intra-molecule interactions. The interactions between the Pt atoms are described by the Sutton-Chen model [29], which is suitable for describing metal-metal interactions in metallic systems.…”

Section: Theorymentioning

confidence: 99%

“…These include the recent work of Liu et al [17] and Selvan et al [18] who were able to show how structural and transport properties of water and hydronium ions at membrane/vapor interface are related to membrane water content. Lamas and Balbuena [19] examined the role of Nafion content in the CL. Malek et al [20] performed a coarse-gained MD simulation based on meso-scale calculations The dependence of the distribution of Pt particle sizes on the fabrication process is well documented [7,[21][22][23] and the distribution has some effect on PEMFC performance [23].…”

Section: Introductionmentioning

confidence: 99%

Effect of Pt nano-particle size on the microstructure of PEM fuel cell catalyst layers: Insights from molecular dynamics simulations

Cheng

Malek

Sui

2010

Electrochimica Acta

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The effect of Pt nano-particles size on the microstructure of catalyst layers in a Polymer Electrolyte Fuel Cell is investigated by means of molecular dynamics simulations. The catalyst layer model includes carbon-supported platinum, perfluorosulfonate ionomer (PFSI), hydronium ions and water molecules. Three different Pt nano-particle sizes, i.e. 1, 2 and 3 nm, are studied, and simulations provide visualization of the distinct micro-morphologies of the CL corresponding to each nano-particle size. The results are analyzed using pair correlation functions, showing that different microstructures are obtained for different Pt nano-particle sizes, and also that inclusion of PFSI in the simulations impacts significantly the final configuration of Pt nano-particles. Water molecules are found to distribute near the side chains of PFSI and surface of Pt nano-particles, but far from the graphite surface. Side chains form clusters and exhibit different dispersion toward the Pt surface. The orientations of the side chains in the vicinity of the Pt surface are analyzed in detail. The dispersion of perfluorosulfonate ionomer is found to strongly influence the merging of Pt nano-particles and, consequently, the CL microstructure formation.

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Molecular dynamics studies of a model polymer–catalyst–carbon interface

Cited by 51 publications

References 25 publications

Molecular dynamics simulations of supported metal nanocatalyst formation by plasma sputtering

Molecular dynamics simulations of supported metal nanocatalyst formation by plasma sputtering

Specifics of solvation of sulfonated polyelectrolytes in water, dimethylmethylphosphonate, and their mixture: A molecular simulation study

Effect of Pt nano-particle size on the microstructure of PEM fuel cell catalyst layers: Insights from molecular dynamics simulations

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