Theoretical studies of Au_m and PtAu_n clusters and their N₂ and O₂ adsorption complexes

Abstract

Small homonuclear Au m (m ≤ 5) and bimetallic PtAu n (n ≤ 4) clusters were studied using density functional theory. Both homonuclear and bimetallic clusters tend to form compact two-dimensional structures. All the low-lying Au m clusters have delocalized highest occupied molecular orbitals (HOMOs), whereas all the PtAu n clusters have more localized HOMOs on the Pt atom. The localized HOMO makes the PtAu n clusters more regioselective toward electrophilic reactions than the Au m clusters. Adsorptions of N 2 and O 2 onto these metal clusters were further studied. In N 2 adsorption, the metal clusters donate their electrons primarily to the σ * orbitals of N 2 to form end-on complexes preferably. In O 2 adsorption, complicated π orbital interactions between the cluster and O 2 dominate to form side-on complexes with relatively larger binding energies.

Reactivity of the free and (5,5)-carbon nanotube-supported AuPt bimetallic clusters towards O2 activation: a theoretical study

“…In particular, the role of composition on the geometrical structure in Au m Pt n clusters with low nuclearity (2 r m + n r 5) has been reported. 111,115 The present results are essentially in agreement with previous studies, with some small differences arising from the use of slightly different computational setups. The results (Fig.…”

“…Density of the bare substrate and the molecule in eqn (3) are taken from the optimized super-system structure through singlepoint calculations. and AuPt binary clusters 103,[110][111][112][113][114] have been extensively studied.…”

Spin–Orbit Coupling Effects in AumPtn Clusters (m + n = 4)

“…Table shows that for Au 4 in the SR case we found three minima in the singlet state with D 2 h , C 2 v , and D 4 h symmetries. D 2 h is the lowest energy isomer, which matches the experimentally reported structure and was characterized in other theoretical studies. − ,− Two minima in the triplet state with D 2 h and D 3 h symmetries and two in the quintet state with D 2 d and T d symmetries were also located. Generally speaking, the singlets are more stable than the triplets, which in turn are more stable than the quintets.…”

“…Information on bimetallic clusters, which are the focus of this work, is not as abundant as that available for monometallic clusters. Au 2 Pt 2 , Au 3 Pt, and AuPt 3 structures have been reported along − with their interactions with CO molecules. − High adsorption energies into MgO films have also been reported. , Sensitive issues in the just mentioned theoretical studies are that the corresponding potential energy surfaces (PESs) were not thoroughly explored and that the spin–orbit (SO) coupling nor the high spin states, which are very relevant for Au/Pt containing clusters, were taken into account.…”

Theoretical DFT study of homonuclear and binary transition-metal dimers

“…Among these, Pt-based [24][25][26][27] and Au-based [28][29][30] dimers have attracted research interest because of their fascinating properties in relation to their homonuclear counterparts. The presence of a second metallic component produces a synergistic effect that improves many of the relevant properties for technological applications, response associated to their electronic structure changes.…”