Preparation of TiO2-supported Au nanoparticle catalysts from a Au13 cluster precursor: Ligand removal using ozone exposure versus a rapid thermal treatment

Laurent D. Menard, Fengting Xu, Ralph G. Nuzzo, Judith C. Yang

Research output: Contribution to journalArticlepeer-review

Abstract

The structure of Au heterogeneous catalysts on the anatase form of TiO2 has been characterized by high-resolution electron microscopy (HREM) and quantitative Z-contrast scanning transmission electron microscopy (STEM). These materials are prepared by deposition of highly monodisperse Au13[PPh3]4[S(CH2)11CH3]4 (8-Å diameter) ligand-protected clusters on anatase, followed by reaction with ozone or a rapid oxidative thermal treatment to remove the ligands. The materials obtained differ markedly in each case. For the thermal treatment at 400 °C in air, the supported particles grow to an average size of 2.7 nm (± 0.6   nm) in diameter, and the larger particles in the distribution are found to adopt a spherical geometry. Particle growth is greatly inhibited when ozone is used to remove the ligands (average diameter 1.2 ± 0.5   nm). These particles assume a more oblate geometry, consistent with a truncated hemispherical shape. It was found that subsequent thermal treatments of the ozone-derived supported nanoparticles at 400 °C in air did not induce additional growth, indicating that sintering is strongly affected by the particle-support interactions developed by the ozone-based low-temperature ligand removal step. These materials exhibit catalytic activity and high stability for the oxidation of CO at elevated temperatures, with the level of activity dependent on catalyst preparation.

Original languageEnglish (US)
Pages (from-to)64-73
Number of pages10
JournalJournal of Catalysis
Volume243
Issue number1
DOIs
StatePublished - Oct 1 2006

Keywords

  • Au catalysis
  • Cluster precursor
  • Electron microscopy
  • HAADF-STEM

ASJC Scopus subject areas

  • Catalysis
  • Process Chemistry and Technology

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