Following Ostwald ripening in nanoalloys by high-resolution imaging with single-atom chemical sensitivity

Journal Article · Mon Sep 17 00:00:00 EDT 2012 · Applied Physics Letters

DOI:https://doi.org/10.1063/1.4754111· OSTI ID:22080446

Alloyeau, D; Nelayah, J; Wang, G; Ricolleau, C ^[1]; Oikawa, T ^[1]

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1. Laboratoire Materiaux et Phenomenes Quantiques, Universite Paris Diderot/CNRS, UMR 7162, Batiment Condorcet, 4 rue Elsa Morante, 75205 Paris Cedex 13 (France)

Several studies have shown that substantial compositional changes can occur during the coarsening of bimetallic nanoparticles (CoPt, AuPd). To explain this phenomenon that could dramatically impacts all the technologically relevant properties of nanoalloys, we have exploited the sensitivity of the latest generation of electron microscope to prove that during the beam-induced coarsening of CoPt nanoparticles, the dynamic of atom exchanges between the particles is different for Co and Pt. By distinguishing the chemical nature of individual atoms of Co and Pt, while they are diffusing on a carbon film, we have clearly shown that Co atoms have a higher mobility than Pt atoms because of their higher evaporation rate from the particles. These atomic-scale observations bring the experimental evidence on the origin of the compositional changes in nanoalloys induced by Ostwald ripening mechanisms.

• OSTI ID: 22080446
• Journal Information: Applied Physics Letters, Vol. 101, Issue 12; Other Information: (c) 2012 American Institute of Physics; Country of input: International Atomic Energy Agency (IAEA); ISSN 0003-6951
• Country of Publication: United States
• Language: English

Related Subjects

77 NANOSCIENCE AND NANOTECHNOLOGY
BEAMS
CARBON
COBALT ALLOYS
COBALT COMPOUNDS
ELECTRON MICROSCOPES
EVAPORATION
FILMS
GOLD COMPOUNDS
NANOSTRUCTURES
PALLADIUM COMPOUNDS
PLATINUM ALLOYS
PLATINUM COMPOUNDS
RESOLUTION
SENSITIVITY
TRANSMISSION ELECTRON MICROSCOPY