Kinetics of CO Oxidation Catalyzed by Highly Dispersed CeO2-Supported Gold

Journal Article · Tue Jan 01 04:00:00 EST 2008 · Journal of Catalysis

DOI:https://doi.org/10.1016/j.jcat.2008.09.012· OSTI ID:980297

Aguilar-Guerrero, V; Gates, B

CeO2-supported gold synthesized from Au(CH3)2(acac) (acac: acetylacetonate) catalyzed CO oxidation at 353 K, with a turnover frequency TOF of 6.3 x 10-3 molecules of CO (Au atom s)-1 at CO and O2 partial pressures of 1.0 kPa; the apparent activation energy was 138 {+-} 2 kJ mol-1. The activity increased as the catalyst functioned in a flow reactor, and after 48 h on stream, the TOF at 298 K and the aforementioned CO and O2 partial pressures was (5.6 {+-} 0.2) x 10-2 molecules of CO (Au atom s)-1. X-ray absorption spectra, reported separately, showed that the catalyst structure changed during operation, as the mononuclear cationic species present initially formed clusters consisting on average of roughly 15 Au atoms each. The gold clusters were more active for CO oxidation catalysis than the mononuclear gold species. Reaction orders of CO oxidation catalyzed by the sample containing the clusters at 303 K were found to be 0.19 in CO, 0.18 in O2, and -0.4 in CO2. The apparent activation energy characterizing the catalyst containing the clusters was found to be only about one-third of that characterizing the catalyst incorporating the mononuclear cationic gold.

• Research Organization: Brookhaven National Laboratory (BNL) National Synchrotron Light Source
• Sponsoring Organization: Doe - Office Of Science
• DOE Contract Number: AC02-98CH10886
• OSTI ID: 980297
• Report Number(s): BNL--93215-2010-JA
• Journal Information: Journal of Catalysis, Journal Name: Journal of Catalysis Journal Issue: 2 Vol. 260; ISSN 0021-9517; ISSN JCTLA5
• Country of Publication: United States
• Language: English

Related Subjects

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CHEMISTRY
ABSORPTION SPECTRA
ACTIVATION ENERGY
ATOMS
CATALYSIS
CATALYSTS
CERIUM OXIDES
GOLD
KINETICS
OXIDATION
PARTIAL PRESSURE
national synchrotron light source