A new method for mapping the three-dimensional atomic distribution within nanoparticles by atom probe tomography (APT)

•Pd and Pt/C nanoparticles were embedded in Ni films by means of electrophoresis and electrodeposition.•Atom Probe Tomography (APT) specimens were fabricated from the embedded nanoparticles using focused ion beam milling.•While Pt/C specimens showed uneven field evaporation and reconstruction artifa...

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Veröffentlicht in:Ultramicroscopy 2018-07, Vol.190, p.30-38
Hauptverfasser: Kim, Se-Ho, Kang, Phil Woong, Park, O Ok, Seol, Jae-Bok, Ahn, Jae-Pyoung, Lee, Ji Yeong, Choi, Pyuck-Pa
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Sprache:eng
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Zusammenfassung:•Pd and Pt/C nanoparticles were embedded in Ni films by means of electrophoresis and electrodeposition.•Atom Probe Tomography (APT) specimens were fabricated from the embedded nanoparticles using focused ion beam milling.•While Pt/C specimens showed uneven field evaporation and reconstruction artifacts, mass spectra and APT reconstructions of high data integrity could be obtained for the Pd nanoparticle specimens. We present a new method of preparing needle-shaped specimens for atom probe tomography from freestanding Pd and C-supported Pt nanoparticles. The method consists of two steps, namely electrophoresis of nanoparticles on a flat Cu substrate followed by electrodeposition of a Ni film acting as an embedding matrix for the nanoparticles. Atom probe specimen preparation can be subsequently carried out by means of focused-ion-beam milling. Using this approach, we have been able to perform correlative atom probe tomography and transmission electron microscopy analyses on both nanoparticle systems. Reliable mass spectra and three-dimensional atom maps could be obtained for Pd nanoparticle specimens. In contrast, atom probe samples prepared from C-supported Pt nanoparticles showed uneven field evaporation and hence artifacts in the reconstructed atom maps. Our developed method is a viable means of mapping the three-dimensional atomic distribution within nanoparticles and is expected to contribute to an improved understanding of the structure-composition-property relationships of various nanoparticle systems.
ISSN:0304-3991
1879-2723
DOI:10.1016/j.ultramic.2018.04.005