Stability of Gold and Platinum Nanowires on Graphite Edges

Abstract

The stability of coinage and noble metal nanowires supported on graphite steps is examined by density functional theory. In particular, we study the stability of supported gold and platinum wires and compare their chemical properties with those of surfaces and bare wires. A substantially stronger bond with graphite was found for platinum wires due to unfilled antibonding states, which are occupied in the case of gold. This difference has direct consequences for the adsorption of hydrogen. This reaction can occur either on the wire or directly on graphite steps. In the case of gold, the reaction is favoured on steps, while on platinum wires, it has no thermodynamical preferences. Our results suggest that, in early stages of wire formation, hydrogen could desorb gold from graphite, but not platinum.

Stability and Hydrogen Affinity of Graphite-Supported Wires of Cu, Ag, Au, Ni, Pd, and Pt

“…In a previous work we have investigated Pt and Au wires at the zigzag edge of graphite sheets. 32 In this work we extend our study to six metals (Ni, Pd, Pt, Cu, Ag, and Au) forming wires at the two stable graphite step edges: zigzag and armchair steps (see Figures 1 and 2). The catalytic properties for hydrogen oxidation are also investigated.…”

“…We leave the cases of oxygen structures for a future study. In a previous work we have investigated Pt and Au wires at the zigzag edge of graphite sheets . In this work we extend our study to six metals (Ni, Pd, Pt, Cu, Ag, and Au) forming wires at the two stable graphite step edges: zigzag and armchair steps (see Figures and ).…”

Recent Progress in Hydrogen Electrocatalysis

“…However, it is known that isolated wires are impractical as electrocatalysts. Therefore, we focus in more realistic systems, where these nanowires are supported on inert substrates to examine their stability and the influence of their chemical properties on the electrocatalytic activity (for details, see [32]). Specifically, we considered Pt and Au monoatomic wires attached to monoatomic steps on the basal planes of graphite, the so-called graphite-supported wires (GSW).…”

“…Considering the sp 2 hybridization of the carbon orbitals and the distance between two unsaturated carbon atoms (2.46Å), which fits quite well the bond distances of the bare wires (≈2.50Å), the zigzag arrangement was taken as the initial configuration. The system is shown in Figure 9-more detailed information can be found in [32].…”

Spontaneous formation of metallic nanostructures on highly oriented pyrolytic graphite (HOPG): an ab initio and experimental study

“…In previous works, we have performed ab initio investigations of both freestanding metal NW 23 and supported on step-edges. 24,25 More recently, we have found that in O 2 /H 2 atmosphere, the graphene edges are mainly oxidized. 26 On the armchair edges, the terminal carbons are carboxyl groups, but on the zigzag edges, we have found stable ketones and aldehyde groups.…”