High resolution HAADF characterization of Ir/TiO2 catalyst reduced at 500 °c: Intensity profile analysis

Orlando Hernández-Cristóbal, Jesús Arenas-Alatorre, Gabriela Díaz, Daniel Bahena, Miguel J. Yacamán

Research output: Contribution to journalArticlepeer-review

14 Scopus citations

Abstract

A comparison is presented between experimental and simulated high resolution-high angle annular dark field images (HR-HAADF) of Ir/TiO2 catalyst reduced at 500 °C where classical strong metal-support interaction develops. The analysis is based on integrated intensity profiles of the atomic columns of iridium nanoparticles on the TiO2 support. The results were as expected, that when Ir/TiO2 catalyst is reduced at high temperature, partially reduced species from the support (TiOx) migrate to the surface of iridium nanoparticles. Two very important facts can be highlighted: one is that the Ti atoms sited on atomic columns in the [11¯0] direction preserve the atomic ordering of the metallic particle (epitaxial growth), while those located in atomic columns at perpendicular directions to the observation axis are disordered, and as a consequence, they appear as an amorphous thin film. Finally, changes in the (111) interplanar spacing of TiO2-rutile structure could be due to an enrichment of Ti3+ species at the rutile surface.

Original languageEnglish (US)
Pages (from-to)11672-11678
Number of pages7
JournalJournal of Physical Chemistry C
Volume119
Issue number21
DOIs
StatePublished - May 28 2015
Externally publishedYes

ASJC Scopus subject areas

  • Electronic, Optical and Magnetic Materials
  • Energy(all)
  • Physical and Theoretical Chemistry
  • Surfaces, Coatings and Films

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