Multilayer Structures of Graphene and Pt Nanoparticles: A Multiscale Computational Study

Abstract

Multiscale simulation study results of multilayer structures consisting of graphene sheets with embedded Pt nanoparticles is reported. Density functional theory is used to understand the energetics of Pt–graphene interfaces and provide reference data for the parameterization of a Pt–graphene interaction potential. Molecular dynamics simulations then provide the conformation and energetics of graphene sheets with embedded Pt nanoparticles of varying density, form, and size. These results are interpreted using a continuum mechanical model of sheet deformation, and serve to parameterize a meso‐scale Monte Carlo model to investigate the question under which conditions the free volume around the Pt nanoparticles forms a percolating cluster, such that the structures can be used in catalytic applications. This article is concluded with a discussion of potential applications of such multilayer structures.

An Improved Approach to Manufacture Carbon Nanotube Reinforced Magnesium AZ91 Composites with Increased Strength and Ductility

“…We should note that although the pull-out force and pull-out energy increases by Pt-coating, the interface characteristics between Pt and CNT is of physically adsorbed type in which no chemical bondings between metal and CNTs are formed [61][62][63]. The only commitment between metal and CNT in this model is the weak physical interactions, which will disappear under the shear stress of less than 50 MPa [49]. Therefore, CNTs, independent on their length, start to slide inside the matrix and get pulled out as soon as the matrix ruptures, and they have little significant load-transfer strengthening effects on the Mg matrix.…”

“…A Morse potential of the form E M = D M [e −2α(r−r 0 ) − 2e −α(r−r 0 ) ] was used for describing Pt-C interactions, where r is the bond distance, r 0 the equilibrium bond distance, D M is the well depth, and α controls the stiffness of the potential. The parameters for Pt-C morse potentials are D M = 0.0071 eV, r 0 = 4.18 Å, and α= 1.05 Å −1 [49].…”

“…Si et al [48] showed that the decoration of exfoliated graphene sheets with Pt nanoclusters prevents face-to-face graphene aggregation. Atomistic simulation study of multilayer structure of graphene and Pt nanoparticle found an optimum nanoparticle density where the adhesive energy of the structure is lowest, and thus, the separation of the graphene sheets is the most easy [49].…”

An improved approach to manufacture CNT reinforced magnesium AZ91 composites with increased strength and ductility

“…([53, 58, 59]). The only commitment between metal and CNT in this model is the weak physical interactions, which will disappear under the shear stress of less than 50 MPa ( [47]). Therefore, CNTs, independent on their length, start to slide inside the matrix and get pulled out as soon as the matrix ruptures, and have little significant load-transfer strengthening effect on the Mg matrix.…”

“…Si et al [46] showed that the decoration of exfoliated graphene sheets with Pt nanoclusters prevents face-to-face graphene aggregation. Atomistic simulation study of multilayer structure of graphene and Pt nanoparticle found an optimum nanoparticle density where the adhesive energy of the structure is lowest, and thus the separation of the graphene sheets most easy [47].…”