Adsorption and reactivity during low temperature oxidation of carbon monoxide on Au/TiO2 catalysts studied by rapid response mass spectrometry

Nicholas J. Ossipoff, Noel W. Cant*

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

11 Citations (Scopus)

Abstract

The remarkable activity of Au/TiO2 for CO oxidation at ambient temperature resides in a very high turnover frequency on sites at the interface between the metal and oxide as shown by a study of adsorption and reaction of CO, CO2, and O2 on TiO2 and Au/TiO2. Rapid response mass spectrometry found that adsorption of CO on TiO2 at 300 K is rapidly reversible and less on reduced samples than on oxidized ones, which indicates that the adsorption sites are oxide ions. The amount adsorbed reversibly on reduced Au/TiO2 is less than that on TiO2 itself, but additional quantities are taken up more slowly and irreversibly. Adsorption of O2 is undetectable on a time scale of seconds but that of CO2 is an order of magnitude greater than that of CO. Under catalytic conditions, the oxidation of CO to CO2 on Au/TiO2 starts almost instantly and appears to involve rapid turnover of the irreversibly adsorbed form of CO. There is some concurrent uptake of O2 beyond that required for catalysis on initial exposure and this capacity is increased if reaction mixtures and individual reactants are alternated, possibly due to the generation of reducible interface sites.

Original languageEnglish
Pages (from-to)161-169
Number of pages9
JournalTopics in Catalysis
Volume8
Issue number3-4
Publication statusPublished - Jun 1999

Keywords

  • Au-support interface
  • Au/TiO
  • CO adsorption
  • CO oxidation
  • Low temperature

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