Direct Observation of the Surfaces of Small Metal Crystallites: Rhodium Supported on TiO2

A. David Logan, Ehrich J. Braunschweig, Abhaya K. Datye, David Smith

Research output: Contribution to journalArticle

90 Scopus citations

Abstract

Surfaces of small rhodium crystallites, ca. 5-8 nm in diameter, have been imaged in a 400-kV highresolution transmission electron microscope by using the profile-imaging mode. The observations were facilitated by supporting the metal on nonporous titanium oxide particles of simple geometric shape. Since all the metal was located on the exterior surfaces of the oxide, the formation of surface overlayers during catalytic pretreatments could be studied. Surfaces which were clean after 473 K reduction in hydrogen were covered with amorphous deposits after treatment in H2 at 773 K, and there was a concurrent drop in the chemisorption uptake of H2. Subsequent oxidation at 473 K did not lead to the complete removal of these deposits, even though the chemisorption uptake by the Rh was partially restored. These results confirmed that migration of Ti suboxides was responsible for altered catalytic behavior during the SMSI state.

Original languageEnglish (US)
Pages (from-to)827-830
Number of pages4
JournalLangmuir
Volume4
Issue number4
DOIs
StatePublished - Jul 1 1988

ASJC Scopus subject areas

  • Materials Science(all)
  • Condensed Matter Physics
  • Surfaces and Interfaces
  • Spectroscopy
  • Electrochemistry

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