Heterogeneous nucleation and shape transformation of multicomponent metallic nanostructures

• Published in: Nature materials Vol. 14; no. 2; pp. 215 - 223
• Main Authors: Kwon, Soon Gu, Krylova, Galyna, Phillips, Patrick J., Klie, Robert F., Chattopadhyay, Soma, Shibata, Tomohiro, Bunel, Emilio E., Liu, Yuzi, Prakapenka, Vitali B., Lee, Byeongdu, Shevchenko, Elena V.
• Format: Journal Article
• Language: English
• Published: London Nature Publishing Group UK 01-02-2015; Nature Publishing Group
• Subjects: 121/143; 639/301/357/354; 639/925/357/354; Biomaterials; Condensed Matter Physics; Gold; Growth kinetics; Lattice strain; MATERIALS SCIENCE; Nanostructure; Nanotechnology; Nucleation; Optical and Electronic Materials; Platinum; Seeds; Shells; Sporting goods; Thermodynamic models
• ISSN: 1476-1122; 1476-4660
• DOI: 10.1038/nmat4115

To be able to control the functions of engineered multicomponent nanomaterials, a detailed understanding of heterogeneous nucleation at the nanoscale is essential. Here, by using
in situ
synchrotron X-ray scattering, we show that in the heterogeneous nucleation and growth of Au on Pt or Pt-alloy seeds the heteroepitaxial growth of the Au shell exerts high stress (∼2 GPa) on the seed by forming a core/shell structure in the early stage of the reaction. The development of lattice strain and subsequent strain relaxation, which we show using atomic-resolution transmission electron microscopy to occur through the slip of {111} layers, induces morphological changes from a core/shell to a dumbbell structure, and governs the nucleation and growth kinetics. We also propose a thermodynamic model for the nucleation and growth of dumbbell metallic heteronanostructures.
The detailed nucleation and growth kinetics and the crystal structure of catalytically relevant CoPt
3
/Au, FePt/Au and Pt/Au metal dumbbell nanoparticles have been obtained by
in situ
synchrotron small- and wide-angle X-ray scattering techniques.