Adsorption of metal nanoparticles on carbon substrates and epitaxial graphene: Assessing models for dispersion forces

Abstract

Carbon substrates such as graphite or epitaxial graphene can be employed to support metal nanoparticles for applications in diverse areas of surface science. In this paper, we address the computational modeling of such systems by means of semiempirical potentials, and in particular the possible role of long-range London dispersion forces. Following the Grimme (D2) strategy often used in combination with density-functional theory calculations, we propose some analytical extensions taking into account the crystalline and semi-infinite natures of the substrate and, in the case of epitaxial graphene, the possible screening of the van der Waals interaction by the bulk underlying metal. These ideas are tested in the specific case of platinum nanoparticles deposited on graphene, graphite, and graphene epitaxially grown on Pt(111) modeled using a many-body Brenner-type potential, and validated against available electronic-structure calculations. Systematic optimizations carried out at zero temperature indicate the relative stability of various nanoparticle shapes on their support, for adsorbates containing several thousand atoms. Using molecular dynamics simulations, we shed light on the thermal behavior and emphasize the key role of dispersion forces on the stabilization of the adsorbates at finite temperature. The vibrational properties of graphene layers in contact with a Pt nanoparticle or epitaxially grown on Pt(111) also reveal some clear sensitivity on temperature and strain.

Density-functional tight-binding approach for metal clusters, nanoparticles, surfaces and bulk: application to silver and gold

“…∼2000 electrons, for vertical TDDFT calculations and about two times less for geometry optimizations [176]. In the more specific field of metal clusters and nanoparticles, TDDFT has also been largely applied and is still an active area of current research [69,[177][178][179][180][181][182][183][184][185][186][187]. Despite the theoretical formulation of DFT is based on first-principles and is exact for the ground state, an important problem is the delicate choice of the exchange-correlation functional.…”

2D materials with enhanced thermoelectric (TE) properties

“…For the case of Graphene -Au, the ratio of Δ2D / ΔG is within the limit as reported by Zabel et al [131]. Similarly, the presence of large Au NPs has attributed to significant local tensile strain on the underlying graphene network where adsorption energy increases with the size of NPs [135].…”

Influence of the Underlying Substrate on the Physical Vapor Deposition of Zn-Phthalocyanine on Graphene

“…The electrostatic doping or interfacial charge exchange between graphene and the underlying substrate most likely alters the affinity (i.e., strength of the interaction) between graphene and top adsorbates. This phenomenon has been reported by multiple molecular dynamics (MD) simulations studying other systems. − In the high ZnPc flux deposition regime, the preferential NW growth is observed either on graphene as-grown on Cu or on bare substrates which form quasi-vertical and nearly horizontal high-aspect-ratio crystallites, respectively. In the case of low ZnPc flux deposition regime, the ZnPc crystallites also prefer to adopt NW growth on graphene on Cu, while they prefer to form flat islands on other graphene-coated substrates as evidenced by the AFM images in Figure a–c.…”