Evidence and model for strain-driven release of metal nano-catalysts from perovskites during exsolution

Tae Sik Oh, Ehsan Rahani, Dragos Neagu, John Thomas Sirr Irvine, Vivek Shenoy, Raymond Gorte, John Vohs

Research output: Contribution to journalLetterpeer-review

Abstract

The evolution of the surface morphology during exsolution of Ni from the perovskite, La0.4Sr0.4Ti0.97Ni0.03O3-δ, under reducing conditions was determined using atomic force microscopy (AFM). The exsolution process was found to initially induce the formation of a 20-30 nm deep pit on the oxide surface followed by the emergence of a Ni particle at the bottom of the pit. Continued emergence of the particle results in it nearly filling the pit producing a unique structure in which the Ni particle is socketed into the oxide surface. We also show that this morphological evolution can be explained using a simple energy-based model that accounts for the interplay between the surface free energy and the strain energy induced by the included metal nucleate. The unique socketed structure results in strong anchorage between the exsolved particles and the oxide host lattice which imparts both high thermal stability and unique catalytic activity.

Original languageEnglish
Pages (from-to)5106–5110
JournalJournal of Physical Chemistry Letters
Volume6
Issue number24
Early online date7 Dec 2015
DOIs
Publication statusPublished - 17 Dec 2015

Keywords

  • Metal exsolution
  • Perovskite
  • Strain
  • Atomic force microscopy

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