OPTIMIZATION and MELTING DYNAMICS of PtAlCu TERNARY NANOALLOY

Ternary nanoalloys are mainly formed by the combination of three different metals and they have attract great interests due to their potential applications in optical, electronic, magnetic, and catalytic fields [1,2]. Important effects in catalytic activities on metal surfaces are the alloying effect, size and composition [3,4]. Especially, the Pt-alloy catalysts have drawn most of attention. Since the surface structures of Pt-alloys strongly affect the catalytic performance, a thorough study of their surface structures is important for the syntheses and applications of Pt-alloy catalysts [5] . In this study, a theoretical investigation of PtAlCu ternary nanoalloys, consisting of N = 38 and N = 55 atoms, was carried out by modeling interatomic interactions with the Gupta many-body potential energy function [6,7]. The lowest energy structures for all compositions of Pt6AlnCu32-n (n=0-32) and Pt13AlnCu42-n (n=0-42) ternary nanoalloys were obtained using the Basin Hopping algorithm [8,9] . Pt6Al17Cu15 was determined the most stable structure for Pt6AlnCu32-n and Pt13Al25Cu17 was determined to be the most stable structure for Pt13AlnCu42-n. The melting behavior of the most stable Pt6Al17Cu15 and Pt13Al25Cu17 ternary nanoalloys, found by optimization, were investigated using the Canonical Molecular Dynamics Simulation method [10]. We obtained the melting temperatures of the Pt6Al17Cu15, Pt13Al25Cu17 to be 610 K and 620 K, respectively. The simulation results show that the melting temperatures of PtAlCu nanoalloys vary depending on the composition. Molecular dynamics simulations allow ones to synthesize and develop a new functional nanostructured material by controlling atom types in nanoalloys and by increasing the size of nanoalloys to guide the experimentalists.