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Title: Substrate doping: A strategy for enhancing reactivity on gold nanocatalysts by tuning sp bands
Authors: Mammen, Nisha
de Gironcoli, Stefano
Narasimhan, Shobhana
Keywords: Physical Chemistry
Atomic, Molecular & Chemical Physics
Co Oxidation
Catalyzed Oxidation
Au Nanoclusters
Oxide Support
Mgo Crystals
Doped Mgo
Issue Date: 2015
Publisher: American Institute of Physics
Citation: Journal of Chemical Physics
Mammen, N.; de Gironcoli, S.; Narasimhan, S., Substrate doping: A strategy for enhancing reactivity on gold nanocatalysts by tuning sp bands. Journal of Chemical Physics 2015, 143 (14), 6.
Abstract: We suggest that the reactivity of Au nanocatalysts can be greatly increased by doping the oxide substrate on which they are placed with an electron donor. To demonstrate this, we perform density functional theory calculations on a model system consisting of a 20-atom gold cluster placed on a MgO substrate doped with Al atoms. We show that not only does such substrate doping switch the morphology of the nanoparticles from the three-dimensional tetrahedral form to the two-dimensional planar form, but it also significantly lowers the barrier for oxygen dissociation by an amount proportional to the dopant concentration. At a doping level of 2.78%, the dissociation barrier is reduced by more than half, which corresponds to a speeding up of the oxygen dissociation rate by five orders of magnitude at room temperature. This arises from a lowering in energy of the s and p states of Au. The d states are also lowered in energy, however, this by itself would have tended to reduce reactivity. We propose that a suitable measure of the reactivity of Au nanoparticles is the difference in energy of sp and d states. (C) 2015 AIP Publishing LLC.
Description: Restricted access
ISSN: 0021-9606
Appears in Collections:Research Articles (Shobhana Narasimhan)

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