Topics in Catalysis

, Volume 44, Issue 1, pp 263–273

Reducibility of supported gold (III) precursors: influence of the metal oxide support and consequences for CO oxidation activity

  • Laurent Delannoy
  • Norbert Weiher
  • Nikolaos Tsapatsaris
  • Angela M. Beesley
  • Luanga Nchari
  • Sven L. M. Schroeder
  • Catherine Louis
Article

DOI: 10.1007/s11244-007-0299-3

Cite this article as:
Delannoy, L., Weiher, N., Tsapatsaris, N. et al. Top Catal (2007) 44: 263. doi:10.1007/s11244-007-0299-3

The origin of CO oxidation performance variations between three different supported Au catalysts (Au/CeO2, Au/Al2O3, Au/TiO2) was examined by in situ XAFS and DRIFTS measurements. All samples were prepared identically, by deposition-precipitation of an aqueous Au(III) complex with urea, and contained the same gold loading (~1 wt %). The as-prepared supported Au(III) precursors exhibited different reduction behaviour during exposure to the CO/O2/He reaction mixture at 298 K. The reducibility of the Au(III) precursor was found to decrease as a function of the support material in the order: titania > ceria > alumina. The as-prepared samples were inactive catalysts, but Au/TiO2 and Au/CeO2 developed catalytic activity as the reduction of Au(III) to metallic Au proceeded. Au/Al2O3 remained inactive. The developed catalytic CO oxidation activity at 298 K varied as a function of the support as follows: titania > ceria > alumina ~ 0. The EXAFS of samples pretreated in air at 773 K and in H2 at 573 K reveals the presence of only metallic particles for Au/TiO2 and Au/Al2O3. Au(III) supported on CeO2 remains unreduced after calcination, but reduces during the treatment with H2. CO oxidation experiments performed at 298 K with the activated samples show that the presence of metallic gold is necessary to obtain active catalysts (Au/CeO2 is not active after calcination) and that the reducible supports facilitate the genesis of active catalysts, while metallic gold particles on alumina are not active.

Keywords

goldceriatitaniaaluminareducibilityCO oxidationDRIFTSXAFS

Copyright information

© Springer Science+Business Media, LLC 2007

Authors and Affiliations

  • Laurent Delannoy
    • 1
  • Norbert Weiher
    • 2
  • Nikolaos Tsapatsaris
    • 2
  • Angela M. Beesley
    • 2
  • Luanga Nchari
    • 2
  • Sven L. M. Schroeder
    • 2
    • 3
  • Catherine Louis
    • 1
  1. 1.Laboratoire de Réactivité de Surface, UMR 7609 CNRSUniversité Pierre et Marie Curie-Paris 6France
  2. 2.Molecular Materials Centre, School of Chemical Engineering and Analytical Science The University of ManchesterManchesterUK
  3. 3.School of ChemistryThe University of ManchesterManchesterUK