Imaging Three-Dimensional Elemental Inhomogeneity in Pt-Ni Nanoparticles Using Spectroscopic Single Particle Reconstruction

Yi-Chi Wang, Thomas J. A. Slater, Gerard M. Leteba, Alan M. Roseman, Christopher P. Race, Neil P. Young, Angus I. Kirkland, Candace I. Lang, Sarah J. Haigh

Research output: Contribution to journalArticlepeer-review


The properties of nanoparticles are known to critically depend on their local chemistry but characterising three dimensional (3D) elemental segregation at the nanometer scale is highly challenging. Scanning transmission electron microscope (STEM) tomographic imaging is one of the few techniques able to measure local chemistry for inorganic nanoparticles but conventional methodologies often fail due to the high electron dose imparted. Here, we demonstrate realisation of a new spectroscopic single particle reconstruction approach built on a method developed by structural biologists. We apply this technique to the imaging of PtNi nanocatalysts and find new evidence of a complex inhomogeneous alloying with a Pt-rich core, a Ni-rich hollow octahedral intermediate shell and a Pt-rich rhombic dodecahedral skeleton framework with less Pt at <100> vertices. The ability to gain evidence of local surface enrichment that varies with the crystallographic orientation of facets and vertices is expected to provide significant insight towards the development of nanoparticles for sensing, medical imaging and catalysis.
Original languageEnglish
Pages (from-to)732-738
Number of pages7
JournalNano Letters
Issue number2
Early online date25 Jan 2019
Publication statusPublished - 13 Feb 2019


  • three dimensional reconstruction
  • single particle reconstruction
  • PtNi nanoparticle catalysts
  • energy dispersive X-ray spectroscopy
  • surface segregation
  • scanning transmission electron microscopy

Research Beacons, Institutes and Platforms

  • National Graphene Institute
  • Dalton Nuclear Institute


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