Investigation of structural and energetic behavior of 55-atom Pt–Ag–Au ternary nanoalloys

Abstract

A systematic theoretical investigation of structural and energetic behaviors of 55-atom Pt–Ag–Au ternary nanoalloys has been performed in two different composition systems. We have performed Gupta and Density Functional Theory (DFT) approaches on chosen systems. The Basin-Hopping algorithm is used for structural optimizations of PtnAg[Formula: see text]Au[Formula: see text] ([Formula: see text]–13) and PtnAu[Formula: see text]Ag[Formula: see text] ([Formula: see text]–13) ternary nanoalloys with Gupta many-body potential to model interatomic interactions. Local optimization results show that while the tendency of Au atoms to be located varies according to the composition system, the tendency of Pt and Ag atoms to be located does not change in both. For all compositions of Pt–Ag–Au nanoalloys, the structures with the best chemical ordering were then reoptimized by DFT relaxations and the mixing energies of the Gupta and DFT levels were compared. Our mixing energy analysis showed that PtnAg[Formula: see text]Au[Formula: see text] ([Formula: see text]–13) nanoalloys are not energetically suitable for mixing at both Gupta and DFT level. Also, mixing energy variations of PtnAu[Formula: see text]Ag[Formula: see text] ([Formula: see text]–13) nanoalloys obtained at Gupta level does not agree with the one obtained at DFT level. In addition, it has been found that the minimization energy changes when an atom in the central site is exchanging by an atom in the second shell and surface.