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Title: Effect of Alumina and Titania on the Oxidation of CO over Au Nanoparticles Evaluted by 13C Isotopic Transient Analysis

Abstract

Titania- and alumina-supported Au nanoparticles were synthesized by a deposition-precipitation method and subsequent thermal treatment in He. X-ray absorption spectroscopy at the Au-L{sub III} edge revealed that the as-prepared Au/TiO{sub 2} sample contained cationic Au that was reduced to a predominately metallic state after treatment in He at 623 K. Scanning transmission electron microscopy showed the Au to be highly dispersed over both the metal oxides, with an average particle size of 3.3 nm for Au/TiO{sub 2} and 2.5 nm for Au/Al{sub 2}O{sub 3}. The global rate, apparent activation energy, and orders of reaction with respect to CO and O{sub 2} of CO oxidation were different for the two metal oxide-supported samples. Steady-state isotopic transient kinetic analysis was used to explore the intrinsic turnover frequency (TOF{sub intr}) and coverage of active carbon-containing intermediates ({theta}{sub COx}) that led to carbon dioxide during CO oxidation. After correcting for CO{sub 2} readsorption, the TOF{sub intr} was found to be independent of temperature, approximately 3.4 s{sup -1} for Au/TiO{sub 2} (261-303 K) and 2.1 s{sup -1} for Au/Al{sub 2}O{sub 3} (272-343 K). At 293 K, the coverage of active carbon-containing intermediates was greater over Au/TiO{sub 2} than over Au/Al{sub 2}O{sub 3}. The higher coveragemore » of species-forming product on Au/TiO{sub 2} is attributed to the greater availability of active surface oxygen on a titania catalyst compared with an alumina catalyst.« less

Authors:
; ; ;
Publication Date:
Research Org.:
Brookhaven National Laboratory (BNL) National Synchrotron Light Source
Sponsoring Org.:
Doe - Office Of Science
OSTI Identifier:
914113
Report Number(s):
BNL-78681-2007-JA
Journal ID: ISSN 0021-9517; JCTLA5; TRN: US200804%%316
DOE Contract Number:
DE-AC02-98CH10886
Resource Type:
Journal Article
Resource Relation:
Journal Name: J. Catal.; Journal Volume: 238; Journal Issue: 2
Country of Publication:
United States
Language:
English
Subject:
54 ENVIRONMENTAL SCIENCES; 37 INORGANIC, ORGANIC, PHYSICAL AND ANALYTICAL CHEMISTRY; CARBON MONOXIDE; OXIDATION; CATALYTIC EFFECTS; TITANIUM OXIDES; ALUMINIUM OXIDES; GOLD; ACTIVATION ENERGY; CATALYSIS; REACTION INTERMEDIATES; national synchrotron light source

Citation Formats

Calla,J., Bore, M., Datye, A., and Davis, R. Effect of Alumina and Titania on the Oxidation of CO over Au Nanoparticles Evaluted by 13C Isotopic Transient Analysis. United States: N. p., 2006. Web. doi:10.1016/j.jcat.2006.01.009.
Calla,J., Bore, M., Datye, A., & Davis, R. Effect of Alumina and Titania on the Oxidation of CO over Au Nanoparticles Evaluted by 13C Isotopic Transient Analysis. United States. doi:10.1016/j.jcat.2006.01.009.
Calla,J., Bore, M., Datye, A., and Davis, R. Sun . "Effect of Alumina and Titania on the Oxidation of CO over Au Nanoparticles Evaluted by 13C Isotopic Transient Analysis". United States. doi:10.1016/j.jcat.2006.01.009.
@article{osti_914113,
title = {Effect of Alumina and Titania on the Oxidation of CO over Au Nanoparticles Evaluted by 13C Isotopic Transient Analysis},
author = {Calla,J. and Bore, M. and Datye, A. and Davis, R.},
abstractNote = {Titania- and alumina-supported Au nanoparticles were synthesized by a deposition-precipitation method and subsequent thermal treatment in He. X-ray absorption spectroscopy at the Au-L{sub III} edge revealed that the as-prepared Au/TiO{sub 2} sample contained cationic Au that was reduced to a predominately metallic state after treatment in He at 623 K. Scanning transmission electron microscopy showed the Au to be highly dispersed over both the metal oxides, with an average particle size of 3.3 nm for Au/TiO{sub 2} and 2.5 nm for Au/Al{sub 2}O{sub 3}. The global rate, apparent activation energy, and orders of reaction with respect to CO and O{sub 2} of CO oxidation were different for the two metal oxide-supported samples. Steady-state isotopic transient kinetic analysis was used to explore the intrinsic turnover frequency (TOF{sub intr}) and coverage of active carbon-containing intermediates ({theta}{sub COx}) that led to carbon dioxide during CO oxidation. After correcting for CO{sub 2} readsorption, the TOF{sub intr} was found to be independent of temperature, approximately 3.4 s{sup -1} for Au/TiO{sub 2} (261-303 K) and 2.1 s{sup -1} for Au/Al{sub 2}O{sub 3} (272-343 K). At 293 K, the coverage of active carbon-containing intermediates was greater over Au/TiO{sub 2} than over Au/Al{sub 2}O{sub 3}. The higher coverage of species-forming product on Au/TiO{sub 2} is attributed to the greater availability of active surface oxygen on a titania catalyst compared with an alumina catalyst.},
doi = {10.1016/j.jcat.2006.01.009},
journal = {J. Catal.},
number = 2,
volume = 238,
place = {United States},
year = {Sun Jan 01 00:00:00 EST 2006},
month = {Sun Jan 01 00:00:00 EST 2006}
}