Theoretical investigation of the structures of unsupported 38-atom CuPt clusters

Research output: Contribution to journalArticlepeer-review

Authors

  • Josafat Guerrero-Jordan
  • Roy Johnston
  • José Luis Cabellos
  • Alvaro Posada-Amarillas

Colleges, School and Institutes

External organisations

  • Universidad de Sonora
  • School of Chemistry; University of Birmingham; Edgbaston Birmingham B15 2TT UK

Abstract

A genetic algorithm has been used to perform a global sampling of the potential energy surface in the search for the lowest-energy structures of unsupported 38-atom Cu–Pt clusters. Structural details of bimetallic Cu–Pt nanoparticles are analyzed as a function of their chemical composition and the parameters of the Gupta potential, which is used to mimic the interatomic interactions. The symmetrical weighting of all parameters used in this work strongly influences the chemical ordering patterns and, consequently, cluster morphologies. The most stable structures are those corresponding to potentials weighted toward Pt characteristics, leading to Cu–Pt mixing for a weighting factor of 0.7. This reproduces density functional theory (DFT) results for Cu–Pt clusters of this size. For several weighting factor values, the Cu30Pt8 cluster exhibits slightly higher relative stability. The copper-rich Cu32Pt6 cluster was reoptimized at the DFT level to validate the reliability of the empirical approach, which predicts a Pt@Cu core-shell segregated cluster. A general increase of interatomic distances is observed in the DFT calculations, which is greater in the Pt core. After cluster relaxation, structural changes are identified through the pair distribution function. For the majority of weighting factors and compositions, the truncated octahedron geometry is energetically preferred at the Gupta potential level of theory.

Details

Original languageEnglish
Article number123
Number of pages9
JournalEuropean Physical Journal B
Volume91
Issue number6
Early online date18 Jun 2018
Publication statusPublished - Jun 2018