Trapping of metal atoms in the defects on graphene

Abstract

The binding of a single metal atom (Pt, Pd, Au, and Sn) nearby a single-vacancy (SV) on the graphene is investigated using the first-principles density-functional theory. On the pristine graphene (pri-graphene), the Pt, Pd, and Sn prefer to be adsorbed at the bridge site, while Au prefers the top site. On the graphene with a single-vacancy (SV-graphene), all the metal atoms prefer to be trapped at the vacancy site and appear as dopants. However, the trapping abilities of the SV-graphene are varied for different metal atoms, i.e., the Pt and Pd have the larger trapping zones than do the others. The diffusion barrier of a metal atom on the SV-graphene is much higher than that on the pri-graphene, and the Pt atom has the largest diffusion barrier from the SV site to the neighboring bridge sites. On the SV-graphene, more electrons are transferred from the adatoms (or dopants) to the carbon atoms at the defect site, which induces changes in the electronic structures and magnetic properties of the systems. This work provides valuable information on the selectivity of lattice vacancy in trapping metal atoms, which would be vital for the atomic-scale design of new metal-carbon nanostructures and graphene-based catalysts.

Mobile metal adatoms on single layer, bilayer, and trilayer graphene: Anab initioDFT study with van der Waals corrections correlated with electron microscopy data

“…DFT-calculated adatom binding energies are very sensitive to the exchange correlation functional used. To illustrate this, Table 1 shows binding energies of a single Au adatom on pristine single layer graphene taken from some recent ab-initio DFT studies 9,10,12,17,18, 25 . The local density approximation (LDA) functional is well known to significantly overbind compared to the generalised gradient approximation as parametrised by Perdew, Burke and Ernzerhof 36 (GGA PBE).…”

“…Widespread implementation of graphene-based electronics will therefore involve developing a more detailed understanding of metal-graphene interactions on a fundamental level. To this end, many theoretical studies using density functional theory (DFT) have already emerged which present predictions of binding energies and relaxed structures of various metal adatoms and clusters on pristine single layer graphene 9-24 and on graphene defect structures [25][26][27][28][29][30][31] . Potential contacting applications will depend very much on the metal used because vacancy formation energies can be greatly reduced by certain dopants.…”

“…Ding et al 10 state that they allowed all atomic positions to relax in the direction normal to the graphene plane, but it is unclear whether they also allowed for in-plane relaxations. Tang et al 25 allowed all atoms in the calculation to relax in all directions. Amft et al 18 appear to have used the still different method of fixing the positions of the adatom and the carbon atoms on the supercell perimeter, whilst all other carbon positions were allowed to relaxed.…”

Magnetoresistance of Mn-decorated topological line defects in graphene

“…In general, the intentional introduction of defects into graphene is a topic that currently receives enormous attention, because it can lead to a multitude of applications [8][9][10][11][12][13][14]. Moreover, the interactions between defects in graphene and metal atoms have been explored extensively in the literature [15][16][17][18][19]. Selective deposition of Pt atoms at graphene line defects recently has been demonstrated in Ref.…”

Insight into the mechanism of Pt anchored graphene toward the CHx(x = 1 ∼ 4) reforming under H2 environments

“…However, the migration of nanosized catalyst particles causes their potential accumulation into larger structures, which limit their availability and activity [37,38]. In this regard, the single-atom metallic impurities in graphene has been proved to be stable enough [39,40] and would be utilized in catalytic reaction [41]. Wang et al found an efficient way to create vacancies and filled the vacancies with desired metal dopant [42].…”