Poisoning of the Au/TiO2 active site for CO oxidation by NaBr

Sean M. Oxford, Juan Henao, Jeff H. Yang, Jeffrey T. Miller, Mayfair C. Kung, Harold H Kung

Research output: Chapter in Book/Report/Conference proceedingConference contribution

Abstract

Au/TiO2 is a highly active catalyst for CO oxidation when Au is dispersed as nanoparticles. However, its catalytic activity is suppressed by residual halide. Using a combination of in-situ FTIR spectroscopy, X-ray absorption spectroscopy, and microreactor studies, changes occurring at the active site upon addition of NaBr to reduced and unreduced catalyst were monitored. The active site is Au0, therefore the unreduced catalyst is inactive. Binding of bromide to Au3+ in the unreduced catalyst inhibited reduction to Au0, thereby preventing activation of the catalyst. Bromide also bound to Au0 sites on the reduced catalyst, inhibiting CO adsorption and activation, resulting in lost catalytic activity. In addition to binding to the Au particles, the bromide also mobilized them, resulting in significantly accelerated agglomeration.

Original languageEnglish
Title of host publicationACS National Meeting Book of Abstracts
Publication statusPublished - 2007
Event233rd ACS National Meeting - Chicago, IL, United States
Duration: Mar 25 2007Mar 29 2007

Other

Other233rd ACS National Meeting
CountryUnited States
CityChicago, IL
Period3/25/073/29/07

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Carbon Monoxide
Oxidation
Catalysts
Bromides
Catalyst activity
Chemical activation
X ray absorption spectroscopy
Agglomeration
Nanoparticles
Adsorption

ASJC Scopus subject areas

  • Chemistry(all)

Cite this

Oxford, S. M., Henao, J., Yang, J. H., Miller, J. T., Kung, M. C., & Kung, H. H. (2007). Poisoning of the Au/TiO2 active site for CO oxidation by NaBr. In ACS National Meeting Book of Abstracts

Poisoning of the Au/TiO2 active site for CO oxidation by NaBr. / Oxford, Sean M.; Henao, Juan; Yang, Jeff H.; Miller, Jeffrey T.; Kung, Mayfair C.; Kung, Harold H.

ACS National Meeting Book of Abstracts. 2007.

Research output: Chapter in Book/Report/Conference proceedingConference contribution

Oxford, SM, Henao, J, Yang, JH, Miller, JT, Kung, MC & Kung, HH 2007, Poisoning of the Au/TiO2 active site for CO oxidation by NaBr. in ACS National Meeting Book of Abstracts. 233rd ACS National Meeting, Chicago, IL, United States, 3/25/07.
Oxford SM, Henao J, Yang JH, Miller JT, Kung MC, Kung HH. Poisoning of the Au/TiO2 active site for CO oxidation by NaBr. In ACS National Meeting Book of Abstracts. 2007
Oxford, Sean M. ; Henao, Juan ; Yang, Jeff H. ; Miller, Jeffrey T. ; Kung, Mayfair C. ; Kung, Harold H. / Poisoning of the Au/TiO2 active site for CO oxidation by NaBr. ACS National Meeting Book of Abstracts. 2007.
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AB - Au/TiO2 is a highly active catalyst for CO oxidation when Au is dispersed as nanoparticles. However, its catalytic activity is suppressed by residual halide. Using a combination of in-situ FTIR spectroscopy, X-ray absorption spectroscopy, and microreactor studies, changes occurring at the active site upon addition of NaBr to reduced and unreduced catalyst were monitored. The active site is Au0, therefore the unreduced catalyst is inactive. Binding of bromide to Au3+ in the unreduced catalyst inhibited reduction to Au0, thereby preventing activation of the catalyst. Bromide also bound to Au0 sites on the reduced catalyst, inhibiting CO adsorption and activation, resulting in lost catalytic activity. In addition to binding to the Au particles, the bromide also mobilized them, resulting in significantly accelerated agglomeration.

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