Bonding of Gold Nanoclusters on Graphene with and without Point Defects

Abstract

Hybrid nanostructures of size-selected nanoparticles (NPs) and 2D materials exhibit striking physical and chemical properties and are attractive for many technology applications. A major issue for the performance of these applications is device stability. In this work, we investigate the bonding of cuboctahedral, decahedral and icosahedral Au NPs comprising 561 atoms on graphene sheets via 103-atom scale ab initio spin-polarized calculations. Two distinct cases we considered: (i) the Au NPs sit with their (111) facets on graphene and (ii) the NPs are oriented with a vertex on graphene. In both cases, we compare the binding energies with and without a graphene vacancy under the NP. We find that in all cases, the presence of the graphene vacancy enhances the bonding of the NPs. Significantly, in the vertex-on-graphene case, the binding energy is considerably increased by several eVs and becomes similar to the (111) facet-on-graphene case. The strain in the NPs is found to be minimal and the displacement of the carbon atoms in the immediate neighborhood of the vacancy is on the 0.1 Å scale. The work suggests the creation of stable NP-graphene systems for a variety of electronic, chemical and photonic applications.

Interaction of graphene with Au n clusters: a first-principles study

“…In the last decade, Au nanoparticle (NP)graphene nanostructures have been fabricated, among others for sensing applications [26][27][28]. Recent theoretical studies on large scale models showed that the shape of the NPs is largely preserved upon their adsorption on graphene, and that the presence of vacancies strenghthens the bond with the NPs [29]. In addition, the comparsion of the reactivity of isolated and graphene supported Au NPs for molecular O2 dissociation showed similar geometries and energy profiles, indicating that the interaction between graphene and NPs has a limited effect on the NP's electronic properties [30].…”

Carbide-mediated catalytic hydrogenolysis: defects in graphene on a carbonaceous lithium host for liquid and all-solid-state lithium metal batteries

“…Vacancy defects in the graphene shell can lower the activation energy for Au nucleation and promote the nucleation for a small Au cluster because of energetic defect sites. 47,48 On this account, because the galvanic replaced CM-hy-C (GR|CM-hy-C) also has numerous vacancy defects in its graphene shells, these defects can act as a guidance for Au nano-dot nucleation with a highly confined size (<10 nm) (Fig. S17, ESI†).…”

Stabilization of 2D Raft Structures of Au Nanoclusters with up to 60 Atoms by a Carbon Support

“…The trigonal and hexagonal 2D NPs were interfaced to graphene in accordance with the energetically favorable configuration of refs. [23,24]: the atoms of these (111) slabs were accommodated alternately on top of C atoms and in the middle of C hexagons. This particular configuration forced a lattice constant of 4.031 Å on the gold lattice-down from 4.101 Å.…”

“…The equilibrium distance between the NPs and the graphene sheet was ≈3.30 Å, the same value previously reported in the literature. [23,24] The octahedral, decahedral, and icosahedral NPs were interfaced with one of their (111) facets on graphene in the same way. After placing the clusters on graphene, the models were relaxed with all the atoms in the simulations allowed to move.…”

“…An example of a special cluster-support interaction is that of Au clusters deposited on graphene: the triangular lattice of the (111) surface of the fcc metals is a good symmetry match for the hexagonal honeycomb lattice of graphene, and Au is accommodated on graphene with small lateral strain, relatively weak binding and large Au-C equilibrium separation. [21][22][23] An example of how the support changes the transition from 2D to 3D structures on other supports is given in ref. [24], where Au n (n = 1-20) on rutile TiO 2 (110) surfaces was found to prefer planar or quasi-planar structures.…”