Genesis of a Cerium Oxide-Supported Gold Catalyst for CO Oxidation: Transformation of Mononuclear Gold Complexes into Clusters as Characterized by X-Ray Absorption Spectroscopy

Journal Article · Thu Jan 01 04:00:00 EST 2009 · Journal of Physical Chemistry C

DOI:https://doi.org/10.1021/jp808567a· OSTI ID:980222

Aguilar-Guerrero, V; Lobo-Lapidus, R; Gates, B

CeO{sub 2}-supported mononuclear gold species synthesized from Au(CH{sub 3}){sub 2}(acac) catalyzed CO oxidation at 353 K, with a turnover frequency of 6.5 x 10{sup -3} molecules of CO (Au atom s){sup -1} at CO and O{sub 2} partial pressures of 1.0 and 0.5 kPa, respectively. As the catalyst functioned in a flow reactor, the activity increased markedly so that within about 10 h the conversion of CO had increased from about 1% to almost 100%. Activated catalyst samples were characterized by X-ray absorption spectroscopy and found to incorporate clusters of gold, which increased in size, undergoing reduction, with increasing time of operation. The X-ray absorption near-edge structure spectrum of the catalyst used for the longest period was indistinguishable from that characterizing gold foil. Extended X-ray absorption fine structure data characterizing the catalyst after the longest period of operation indicated the presence of clusters of approximately 30 Au atoms each, on average. The evidence that the catalytic activity increased as the clusters grew is contrasted with earlier reports pointing to increasing activity of supported gold clusters as they were made smallerin a cluster size range largely exceeding ours.

• Research Organization: Brookhaven National Laboratory (BNL) National Synchrotron Light Source
• Sponsoring Organization: Doe - Office Of Science
• DOE Contract Number: AC02-98CH10886
• OSTI ID: 980222
• Report Number(s): BNL--93140-2010-JA
• Journal Information: Journal of Physical Chemistry C, Journal Name: Journal of Physical Chemistry C Journal Issue: 8 Vol. 113; ISSN 1932-7447
• Country of Publication: United States
• Language: English

Related Subjects

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CHEMISTRY
ABSORPTION
ABSORPTION SPECTROSCOPY
ATOMS
CATALYSTS
CERIUM
CERIUM OXIDES
FINE STRUCTURE
GOLD
GOLD COMPLEXES
ORIGIN
OXIDATION
PARTIAL PRESSURE
TRANSFORMATIONS
national synchrotron light source