A theoretical study of CO adsorption on gold by Hückel theory and density functional theory calculations

Sun, Keju; Kohyama, Masanori; Tanaka, Shingo; Takeda, Seiji

doi:10.1002/jcc.21913

Cited by 13 publications

(12 citation statements)

References 44 publications

(45 reference statements)

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“…This implies that the smaller coordination number of gold atoms on the stepped Au(321) surface compared to those on Au (111) and Au(100) surfaces should induce the stronger Au-O bond, namely, higher reactivity. The property of less coordinated gold atoms with higher activity is consistent with that found in CO adsorption on gold [27]. Furthermore, this implies the possibility that neighboring gold atoms may hinder the reactivity of gold on (111) and (100) Figure 1g) is stronger than that on the Au(111) surface (Figure 1h).…”

Section: Resultssupporting

confidence: 79%

Understanding of the activity difference between nanogold and bulk gold by relativistic effects

Sun

Kohyama

Tanaka

et al. 2015

Journal of Energy Chemistry

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It is a challenge to thoroughly understand the astonishing difference in catalytic activity between nano gold and bulk gold for some oxidation reactions. In this work, the Au-O interactions in various surroundings were investigated by DFT calculations and compared with the Ag-O interactions. We have found the three points. First, only Au-O bond can be significantly strengthened by the linear O-Au-O structure. Second, the Au-O bond is always stronger than the Ag-O bond when the bonds are embedded in common surroundings. Third, the Au-O bond becomes weaker than the Ag-O bond when the number of neighboring Au atoms becomes large, because the Au-O interactions are suppressed by the presence of neighboring gold atoms. The origin of © 2015. This manuscript version is made available under the Elsevier user license http://www.elsevier.com/open-access/userlicense/1.0/ these three points can be attributed to wider spatial extension of d orbitals of gold, induced by strong relativistic effects. The strong relativistic effects make nano gold with smaller coordinate numbers highly active due to the ease in forming strong Au-O bonds, especially for the O-Au-O bond, whereas gold atoms in bulk with larger coordination numbers chemically inert due to the strong suppression by neighboring gold atoms destabilizing the O-Au-O bond.

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Section: Resultssupporting

confidence: 79%

Understanding of the activity difference between nanogold and bulk gold by relativistic effects

Sun

Kohyama

Tanaka

et al. 2015

Journal of Energy Chemistry

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“…More importantly, the atomic structure at the perimeter interface, the most probable reaction sites of the catalysts, is not structurally rigid. Ab-initio analyses by Sun et al have suggested possible models for the dissociation of oxygen molecules at the perimeter interface in some accordance with Cscorrected ETEM observations [73][74][75][76].…”

Section: Reaction Sitesmentioning

confidence: 53%

Environmental transmission electron microscopy for catalyst materials using a spherical aberration corrector

2015

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“…The CO 2π* ← Au 5d back-donation is less affected by the charge on Au, and therefore, its contribution to the overall interaction between CO and Au along with electrostatic effects makes the interaction attractive. (Some authors argued that for CO adsorbed on Au surfaces CO 5σ → Au σ bonding should be more important than CO 2π* ← Au 5d back-donation when CO adsorbs on top of a surface Au atom; , however, these two contributions are difficult to separate, and it seems that for CO bound to partially negatively charged Au the π back-donation from Au to CO and electrostatic interactions may become the main bonding components). This unfavorable (in view of the weakened donation part) CO-bonding situation triggers the discussed structural rearrangement, i.e., the extraction of the Au atom interacting with CO out of the Au(111) terrace and the formation of a stable Au–CO carbonyl moiety in which the Au atom becomes slightly positively charged (+0.11 e ).…”

Section: Resultsmentioning

confidence: 99%

Transient Au–CO Complexes Promote the Activity of an Inverse Ceria/Gold Catalyst: An Insight from Ab Initio Molecular Dynamics

Bäumer

et al. 2021

J. Phys. Chem. C

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To probe particle−support interactions and their mechanistic role for catalytic CO oxidation on nanoporous gold (np-Au) coated with ceria nanoparticles, we carried out ab initio molecular dynamics (AIMD) simulations and standard density functional theory (static DFT) computations. To this end, we studied ceria clusters (Ce 10 O 20/19 ) supported on a Au(321) surface exhibiting a high density of steps and kinks. Our theoretical model represents the structurally inverse situation compared to more commonly studied ceria-supported Au nanoparticle systems. In agreement with previous results for Au (111), we find that reduced (Ce 10 O 19 ) as well as stoichiometric (Ce 10 O 20 ) ceria nanoparticles transfer electrons to the Au(321) support. This charge transfer (particularly strong in the case of Ce 10 O 19 ) reflecting a strong chemical interaction between ceria and Au is probably responsible for the stabilization of np-Au against thermal coarsening experimentally observed upon deposition of oxide nanoparticles. The adsorption energies of the ceria cluster on Au(321) are more negative than on the Au(111) surface by around ∼0.5 eV. AIMD simulations were employed to study the mechanism of catalytic CO oxidation with O 2 for the ceria/Au(321) system. We found that a CO molecule adsorbed near the ceria/gold perimeter interface can extract a Au atom from the surface in the form of a mobile linear Au−CO complex, which results in a very low activation energy when this species reacts with lattice O to CO 2 . The released bare Au adatom subsequently attaches to a step edge of the gold surface, leading to a dynamic restructuring of the Au support. Next, an activated O 2 molecule adsorbed at a perimeter site between ceria and Au reacts with a second CO molecule to CO 2 and an adsorbed O atom, which eventually fills the vacancy site created in the first half of the cycle. As compared to ceria particles supported on Au(111), the reactivity is enhanced as a new low-energy mechanism is enabled, revealing the positive impact of the stepped structure of Au(321).

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A theoretical study of CO adsorption on gold by Hückel theory and density functional theory calculations

Cited by 13 publications

References 44 publications

Understanding of the activity difference between nanogold and bulk gold by relativistic effects

Understanding of the activity difference between nanogold and bulk gold by relativistic effects

Environmental transmission electron microscopy for catalyst materials using a spherical aberration corrector

Transient Au–CO Complexes Promote the Activity of an Inverse Ceria/Gold Catalyst: An Insight from Ab Initio Molecular Dynamics

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