Role of Au−C Interactions on the Catalytic Activity of Au Nanoparticles Supported on TiC(001) toward Molecular Oxygen Dissociation

High-resolution photoemission and density functional calculations on realistic slab surface models were used to study the interaction and subsequent dissociation of O2 with Au nanoparticles supported on TiC(001). The photoemission results indicate that at 150 K O2 adsorbs molecularly on the supporte...

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Bibliographic Details
Published in:Journal of the American Chemical Society 2010-03, Vol.132 (9), p.3177-3186
Main Authors: Rodríguez, José A, Feria, Leticia, Jirsak, Tomas, Takahashi, Yoshiro, Nakamura, Kenichi, Illas, Francesc
Format: Article
Language:English
Subjects:
ALCOHOLS
AMINES
ATOMS
CARBON MONOXIDE
CHEMISORPTION
CLEAVAGE
DIRECT REACTIONS
DISSOCIATION
FUNCTIONALS
GOLD
HEATING
national synchrotron light source
NUCLEAR PHYSICS AND RADIATION PHYSICS
OXIDATION
OXYGEN
PHOTOEMISSION
POLARIZATION
SUBSTRATES
THERMODYNAMIC ACTIVITY
TRANSFORMATIONS
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Summary:High-resolution photoemission and density functional calculations on realistic slab surface models were used to study the interaction and subsequent dissociation of O2 with Au nanoparticles supported on TiC(001). The photoemission results indicate that at 150 K O2 adsorbs molecularly on the supported gold nanoparticles, and upon heating to temperatures above 200 K the O2 → 2O reaction takes place with migration of atomic oxygen to the TiC(001) substrate. The addition of Au to TiC(001) substantially enhances the rate of O2 dissociation at room temperature. The reactivity of Au nanoparticles supported on TiC(001) toward O2 dissociation is much larger than that of similar nanoparticles supported either on TiO2(110) or MgO(001) surfaces, where the cleavage of O−O bonds is very difficult. Density functional calculations carried out on large supercells show that the contact of Au with TiC(001) is essential for charge polarization and an enhancement in the chemical activity of Au. Small two-dimensional particles which expose Au atoms in contact with TiC(001) are the most reactive. While O2 prefers binding to Au sites, the O atoms interact more strongly with the TiC(001) surface. The oxygen species active during the low-temperature (
ISSN:0002-7863
1520-5126
DOI:10.1021/ja910146g