High Catalytic Activity of Au/CeOx/TiO2(110) Controlled by the Nature of the Mixed Metal Oxide at the Nanometer Level

Journal Article · Thu Jan 01 04:00:00 EST 2009 · Proceedings of the National Academy of Sciences of the United States of America

DOI:https://doi.org/10.1073/pnas.0812604106· OSTI ID:980230

Park, J; Graciani, J; Evans, J; Stacchiola, D; Ma, S; Liu, P; Nambu, A; Sanz, J; Hrbek, J

Mixed-metal oxides play a very important role in many areas of chemistry, physics, materials science, and geochemistry. Recently, there has been a strong interest in understanding phenomena associated with the deposition of oxide nanoparticles on the surface of a second (host) oxide. Here, scanning tunneling microscopy, photoemission, and density-functional calculations are used to study the behavior of ceria nanoparticles deposited on a TiO2(110) surface. The titania substrate imposes nontypical coordination modes on the ceria nanoparticles. In the CeOx/TiO2(110) systems, the Ce cations adopt an structural geometry and an oxidation state (+3) that are quite different from those seen in bulk ceria or for ceria nanoparticles deposited on metal substrates. The increase in the stability of the Ce3+ oxidation state leads to an enhancement in the chemical and catalytic activity of the ceria nanoparticles. The codeposition of ceria and gold nanoparticles on a TiO2(110) substrate generates catalysts with an extremely high activity for the production of hydrogen through the water-gas shift reaction (H2O + CO ? H2 + CO2) or for the oxidation of carbon monoxide (2CO + O2 ? 2CO2). The enhanced stability of the Ce3+ state is an example of structural promotion in catalysis described here on the atomic level. The exploration of mixed-metal oxides at the nanometer level may open avenues for optimizing catalysts through stabilization of unconventional surface structures with special chemical activity.

• Research Organization: Brookhaven National Laboratory (BNL) National Synchrotron Light Source
• Sponsoring Organization: Doe - Office Of Science
• DOE Contract Number: AC02-98CH10886
• OSTI ID: 980230
• Report Number(s): BNL--93148-2010-JA
• Journal Information: Proceedings of the National Academy of Sciences of the United States of America, Journal Name: Proceedings of the National Academy of Sciences of the United States of America Journal Issue: 13 Vol. 106; ISSN PNASA6; ISSN 0027-8424
• Country of Publication: United States
• Language: English

Related Subjects

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CHEMISTRY
CARBON MONOXIDE
CATALYSIS
CATALYSTS
CATIONS
CHEMISTRY
DEPOSITION
EXPLORATION
GEOCHEMISTRY
GOLD
HYDROGEN
OXIDATION
OXIDES
PHOTOEMISSION
PHYSICS
SCANNING TUNNELING MICROSCOPY
STABILITY
STABILIZATION
SUBSTRATES
THERMODYNAMIC ACTIVITY
WATER GAS
national synchrotron light source