Surface segregation of Fe in Pt-Fe alloy nanoparticles: Its precedence and effect on the ordered-phase evolution during thermal annealing

Download
  1. Get@NRC: Surface segregation of Fe in Pt-Fe alloy nanoparticles: Its precedence and effect on the ordered-phase evolution during thermal annealing (Opens in a new window)
DOIResolve DOI: http://doi.org/10.1002/cctc.201500380
AuthorSearch for: ; Search for: ; Search for: ; Search for: ; Search for:
TypeArticle
Journal titleChemCatChem
ISSN1867-3880
Volume7
Issue22
Pages36553664; # of pages: 10
SubjectAnnealing; Characterization; Electrocatalysis; Electron energy levels; Electron energy loss spectroscopy; Electron microscopes; Electron microscopy; Electron scattering; Energy dissipation; Fuel cells; Fuel storage; Image reconstruction; Iron; Nanoparticles; Phase transitions; Platinum; Platinum alloys; Segregation (metallography); Alloy nanoparticle; Atomic-resolution imaging; In-situ electron microscopy; Microscopy technique; Order transformation; Segregation phenomena; Single nanoparticle; Ultrahigh density information storage; Surface segregation
AbstractCoupling electron microscopy techniques with insitu heating ability allows us to study phase transformations on the single-nanoparticle level. We exploit this setup to study disorder-to-order transformation of Pt-Fe alloy nanoparticles, a material that is of great interest to fuel-cell electrocatalysis and ultrahigh density information storage. In contrast to earlier reports, we show that Fe (instead of Pt) segregates towards the particle surface during annealing and forms a Fe-rich FeOx outer shell over the alloy core. By combining both exsitu and insitu approaches to probe the interplay between ordering and surface-segregation phenomena, we illustrate that the surface segregation of Fe precedes the ordering process and affects the ordered phase evolution dramatically. We show that the ordering initiates preferably at the pre-existent Fe-rich shell than the particle core. While the material-specific findings from this study open interesting perspectives towards a controlled phase evolution of Pt-Fe nanoalloys, the characterization methodologies described are general and should prove useful to probing a wide-range of nanomaterials. Surface-segregation vs atomic-ordering: By using atomic-resolution imaging and electron energy loss spectroscopy and employing both exsitu and insitu approaches, an ongoing interplay between segregation and ordering during the thermal annealing of Pt - Fe alloy nanoparticles is studied. Findings reveal a surface segregation of Fe that is in contrast to earlier reports suggesting Pt surface segregation.
Publication date
PublisherWiley
LanguageEnglish
AffiliationNational Research Council Canada; Energy, Mining and Environment
Peer reviewedYes
NPARC number21277392
Export citationExport as RIS
Report a correctionReport a correction
Record identifier409aa1e8-f48b-4eee-a556-bfe53714d340
Record created2016-03-09
Record modified2016-05-09
Bookmark and share
  • Share this page with Facebook (Opens in a new window)
  • Share this page with Twitter (Opens in a new window)
  • Share this page with Google+ (Opens in a new window)
  • Share this page with Delicious (Opens in a new window)