Understanding atom probe tomography of oxide-supported metal nanoparticles by correlation with atomic-resolution electron microscopy and field evaporation simulation

Arun Devaraj, Robert Colby, François Vurpillot, Suntharampillai Thevuthasan

Research output: Contribution to journalArticle

35 Citations (Scopus)

Abstract

Oxide-supported metal nanoparticles are widely used in heterogeneous catalysis. The increasingly detailed design of such catalysts necessitates three-dimensional characterization with high spatial resolution and elemental selectivity. Laser-assisted atom probe tomography (APT) is uniquely suited to the task but faces challenges with the evaporation of metal/insulator systems. Correlation of APT with aberration-corrected scanning transmission electron microscopy (STEM), for Au nanoparticles embedded in MgO, reveals preferential evaporation of the MgO and an inaccurate assessment of nanoparticle composition. Finite element field evaporation modeling is used to illustrate the evolution of the evaporation front. Nanoparticle composition is most accurately predicted when the MgO is treated as having a locally variable evaporation field, indicating the importance of considering laser-oxide interactions and the evaporation of various molecular oxide ions. These results demonstrate the viability of APT for analysis of oxide-supported metal nanoparticles, highlighting the need for developing a theoretical framework for the evaporation of heterogeneous materials.

Original languageEnglish
Pages (from-to)1361-1367
Number of pages7
JournalJournal of Physical Chemistry Letters
Volume5
Issue number8
DOIs
Publication statusPublished - 17 Apr 2014
Externally publishedYes

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Keywords

  • atom probe tomography
  • catalysis
  • field evaporation
  • scanning transmission electron microscopy

ASJC Scopus subject areas

  • Materials Science(all)

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