Real-time imaging and elemental mapping of AgAu nanoparticle transformations

Author(s)

Lewis, E. A. ^[1] ; Slater, T. J. A. ^[1] ; Prestat, E. ^[1] ; Macedo, A. ^[2] ; O'Brien, P. ^{[3, 1]} ; Camargo, P. H. C. ^[2] ; Haigh, S. J. ^[1]

Affiliation

^[1] Univ Manchester, Sch Mat, Manchester M13 9PL, Lancs - England

^[2] Univ Sao Paulo, Inst Quim, Dept Quim Fundamental, BR-05508000 Sao Paulo - Brazil

^[3] Univ Manchester, Sch Chem, Manchester M13 9PL, Lancs - England

• Document type: Journal article
• Source: NANOSCALE; v. 6, n. 22, p. 13598-13605, NOV 2014.
• Web of Science Citations: 38

Abstract

We report the controlled alloying, oxidation, and subsequent reduction of individual AgAu nanoparticles in the scanning transmission electron microscope (STEM). Through sequential application of electron beam induced oxidation and in situ heating and quenching, we demonstrate the transformation of Ag-Au core shell nanoparticles into: AgAu alloyed, Au-Ag core shell, hollow Au-Ag2O core shell, and Au-Ag2O yolk-shell nanoparticles. We are able to directly image these morphological transformations in real-time at atomic resolution and perform energy dispersive X-ray (EDX) spectrum imaging to map changing elemental distributions with sub-nanometre resolution. By combining aberration corrected STEM imaging and high efficiency EDX spectroscopy we are able to quantify not only the growth and coalescence of Kirkendall voids during oxidation but also the compositional changes occurring during this reaction. This is the first time that it has been possible to track the changing distribution of elements in an individual nanoparticle undergoing oxidation driven shell growth and hollowing. (AU)

• FAPESP's process: 13/19861-6 - Controlled metal nanomaterials for catalysis applications
• Grantee: Pedro Henrique Cury Camargo
• Support type: Regular Research Grants