Contrasting motif preferences of platinum and gold nanoclusters between 55 and 309 atoms

Stephanie G Lambie; Geoffrey R Weal; Caroline E Blackmore; Richard E Palmer; Anna L Garden

doi:10.1039/c9na00122k

Contrasting motif preferences of platinum and gold nanoclusters between 55 and 309 atoms

Nanoscale Adv. 2019 May 3;1(6):2416-2425. doi: 10.1039/c9na00122k. eCollection 2019 Jun 11.

Authors

Stephanie G Lambie¹, Geoffrey R Weal¹, Caroline E Blackmore^{2

3}, Richard E Palmer⁴, Anna L Garden¹

Affiliations

¹ Department of Chemistry, University of Otago P.O. Box 56 Dunedin 9054 New Zealand anna.garden@otago.ac.nz +64 3 479 7906 +64 3 479 7928.
² Nanoscale Physics Research Laboratory, School of Physics and Astronomy, University of Birmingham Birmingham B15 2TT UK.
³ School of Chemical Engineering, University of Birmingham Birmingham B15 2TT UK.
⁴ College of Engineering, Swansea University, Bay Campus Fabian Way Swansea SA1 8EN UK R.E.Palmer@swansea.ac.uk.

Abstract

The atomic structure of size-selected Pt clusters in the range 10-600 atoms is investigated with aberration-corrected scanning transmission electron microscopy and reveals significantly different behaviour from the existing data for Au clusters. The Pt clusters show a dominance of the FCC motif from relatively small sizes, whereas traditionally for Au multiple motifs - the icosahedron, decahedron and FCC motifs (and related structures) compete. The new data motivates a comprehensive computational investigation to better understand similarities and differences in the structures and energetics of the two different metallic clusters. Low energy structures of Pt and Au clusters with 55, 101, 147, 228 and 309 atoms (±2%) are identified using a global optimisation algorithm, and the relative energies found by local minimisation using density functional theory. Our computational results support the experimental observations; for Au clusters all motifs are comparably stable over the whole size range, whereas for Pt, the motifs only compete at the smallest sizes, after which the FCC motif is the most stable. Structural analysis suggests the greater tendency of Au towards amorphisation enables the icosahedron and decahedron to remain competitive at larger sizes.