Understanding the Reactivity Properties of Aun (6 ≤ n ≤ 13) Clusters Using Density Functional Theory Based Reactivity Descriptors

De, Himadri Sekhar; Krishnamurty, Saïlaja; Pal, Sourav

doi:10.1021/jp1004852

Cited by 51 publications

(21 citation statements)

References 74 publications

Supporting

Mentioning

Contrasting

Unclassified

Order By: Relevance

“…105 The results of our calculations demonstrate that preferable sites for H 2 adsorption are the positively charged low-coordinated gold atoms in the most stable gold isomers. However, many of these sites are not the best for H 2 dissociation.…”

Section: ■ Results and Discussionmentioning

confidence: 72%

See 1 more Smart Citation

Reactivity of Gold Clusters in the Regime of Structural Fluxionality

et al. 2015

View full text Add to dashboard Cite

This work present results of a systematic investigation of adsorption and dissociation of H 2 on the neutral, positively, and negatively charged gold clusters Au n q (n = 2−11; q = 0, ±1) using the global reaction route mapping (GRRM) technique combined with the anharmonic downward distortion following (ADDF) and the artificial forceinduced reaction (AFIR) methods. An exhaustive search for H 2 dissociation pathways is performed not only on the most stable cluster structures but also on the large number of low-energy isomers, allowing structural transformations between them. The present strategy can automatically identify the structure-dependent lowest transition states (TS) for H 2 dissociation with a systematic procedure in the regime of the structural fluxionality of gold clusters at finite temperature. Temperature effects, cluster isomerization, and influence of the charge state of gold clusters on H 2 adsorption and dissociation are studied. It is demonstrated that the most stable structures of the gold clusters are not always highly reactive, and an ensemble of isomeric structures must be taken into account for adequate description of the reaction rates at finite temperatures. The proposed approach can serve as a promising tool for a systematic analysis and prediction of reactivity of small metal clusters. ■ INTRODUCTIONGold is one of the most intensively studied elements in nanocatalysis due to its unique catalytic activity and selectivity emerging at nanoscale even at room temperatures. 1,2 This feature makes gold a very promising catalyst for the chemical industry and environmental applications. 3,4 The most explored type of catalytic reactions with gold nanoparticles are reactions of oxidation and epoxidation by molecular oxygen, 1,2,5−15 with a strong focus on oxidation of carbon monoxide 1,2,4,9,16−24 as a most simple model case, allowing us to test various approaches and theories. Heterogeneously catalyzed hydrogenation is another type of reaction where gold nanoparticles have shown their great potential as catalysts. 11,25,26 It has been shown that gold nanoparticles supported on the surfaces of some metal oxides can effectively catalyze selective hydrogenation of several classes of organic molecules, including unsaturated aldehydes, ketones, hydrocarbons, and nitro compounds. 26−36 Moreover, gold nanoparticles are very selective for the direct formation of hydrogen peroxide from H 2 and O 2 mixtures. 8,37−40 Dissociative adsorption of molecular hydrogen on gold nanoparticles is the first and one of the most important steps in heterogeneously catalyzed hydrogenation reactions because often it determines the reaction rate. It has been demonstrated that H 2 does not bind to the clean gold bulk surface 41 but adsorbs and dissociates on the supported 11,26,42−49 and free 50−60 gold nanoparticles.Theoretical calculations performed by Corma and coworkers demonstrate that the active sites for H 2 dissociation are usually located at low-coordinated corner or edge positions on a cluster surface and do not dir...

show abstract

Section: ■ Results and Discussionmentioning

confidence: 72%

“…It has been suggested that as a general rule the size and shape of the cluster influence the number and position of available sites for an electrophilic and/or nucleophilic attack. 105 This makes the reactivity patterns of these clusters highly complex.…”

Section: ■ Results and Discussionmentioning

confidence: 99%

Reactivity of Gold Clusters in the Regime of Structural Fluxionality

et al. 2015

View full text Add to dashboard Cite

show abstract

“…For this purpose, we first optimize the structures of the above-mentioned three isomers of the Au 7 cluster at both PBE and TPSS levels, which are provided in the Supporting Information in ascending order of their energies. In conformity with earlier reported data, 39,51,58,59 we also find that planar geometry with C s symmetry represents the ground state of the Au 7 cluster.…”

Section: ■ Results and Discussionmentioning

confidence: 99%

Remarkable Structural Effect on the Gold–Hydrogen Analogy in Hydrogen-Doped Gold Cluster

et al. 2019

View full text Add to dashboard Cite

In accordance with the well established gold–hydrogen analogy, a hydrogen atom mimics the properties of a gold atom in gold clusters. In a recent study it has been demonstrated that the properties of a hydrogen atom doped small gold cluster (Au7H) are not in conformity with the aforementioned analogy. In this paper we study the properties of the Au7H cluster exhaustively to re-examine the validity of the gold–hydrogen analogy in the context of adsorption of CO and O2 molecules on pristine gold and hydrogen atom doped gold clusters. For this purpose we first determine the most stable structure of the Au7H cluster by using an ab initio density functional theory based method with generalized gradient approximation (GGA) and Meta-GGA exchange-correlation functionals. We carry out geometry optimization by considering various planar and three-dimensional isomers of the Au7H cluster as initial geometries. We find that the lowest energy structure of Au7H is a planar one with C 2v symmetry, and it is very close to the structure of the Au8 cluster with D 4h symmetry. Furthermore, to examine the validity of the gold–hydrogen analogy we carry out a detailed investigation of the adsorption of CO and O2 molecules on the most stable as well as various other low energy isomers of the Au7H cluster. We find that the adsorption energies and the extent of activation of CO and O2 molecules on the most stable planar isomer of Au7H are almost the same as those on the parent Au8 cluster with D 4h symmetry proving the validity of the gold–hydrogen analogy. On the other hand, for the high energy three-dimensional isomers of the Au7H cluster obtained from the pristine Au8 cluster with T d symmetry, we find a significant enhancement in adsorption energy as well as the extent of activation of CO and O2 molecules as compared to those for the corresponding pristine cluster. Therefore, the high reactivity of the 3D isomer of the Au7H cluster may be attributed to its existence in a state which is higher in energy than its most stable planar isomer.

show abstract

“…This is consistent with the conclusion reported in the literature. [56][57][58][59][60][61][62] It is reasonable that the substrate surface exerts an important role in determining the structure of supported Au x clusters. Without metal oxide substrate, the structures of Au x clusters will be just determined by the AuÀAu bond strength and arrangement.…”

Section: Effect Of Surface On Au X Cluster Structuresmentioning

confidence: 99%

A DFT Study of the Structures of Au_x Clusters on a CeO₂(111) Surface

Teng

Huang

et al. 2012

ChemPhysChem

View full text Add to dashboard Cite

Studying the structures of metal clusters on oxide supports is challenging due to their various structural possibilities. In the present work, a simple rule in which the number of Au atoms in different layers of Au(x) clusters is changed successively is used to systematically investigate the structures of Au(x) (x=1-10) clusters on stoichiometric and partially reduced CeO(2)(111) surface by DFT calculations. The calculations indicate that the adsorption energy of a single Au atom on the surface, the surface structure, as well as the Au-Au bond strength and arrangement play the key roles in determining Au(x) structures on CeO(2)(111). The most stable Au(2) and Au(3) clusters on CeO(2)(111) are 2D vertical structures, while the most stable structures of Au(x) clusters (x>3) are generally 3D structures, except for Au(7). The 3D structures of large Au(x) clusters in which the Au number in the bottom layer does not exceed that in the top layer are not stable. The differences between Au(x) on CeO(2)(111) and Mg(100) were also studied. The stabilizing effect of surface oxygen vacancies on Au(x) cluster structures depends on the size of Au(x) cluster and the relative positions of Au(x) cluster and oxygen vacancy. The present work will be helpful in improving the understanding of metal cluster structures on oxide supports.

show abstract

Understanding the Reactivity Properties of Au_n (6 ≤ n ≤ 13) Clusters Using Density Functional Theory Based Reactivity Descriptors

Cited by 51 publications

References 74 publications

Reactivity of Gold Clusters in the Regime of Structural Fluxionality

Reactivity of Gold Clusters in the Regime of Structural Fluxionality

Remarkable Structural Effect on the Gold–Hydrogen Analogy in Hydrogen-Doped Gold Cluster

A DFT Study of the Structures of Au_x Clusters on a CeO₂(111) Surface

Contact Info

Product

Resources

About

Understanding the Reactivity Properties of Aun (6 ≤ n ≤ 13) Clusters Using Density Functional Theory Based Reactivity Descriptors

Cited by 51 publications

References 74 publications

Reactivity of Gold Clusters in the Regime of Structural Fluxionality

Reactivity of Gold Clusters in the Regime of Structural Fluxionality

Remarkable Structural Effect on the Gold–Hydrogen Analogy in Hydrogen-Doped Gold Cluster

A DFT Study of the Structures of Aux Clusters on a CeO2(111) Surface

Contact Info

Product

Resources

About

Understanding the Reactivity Properties of Au_n (6 ≤ n ≤ 13) Clusters Using Density Functional Theory Based Reactivity Descriptors

A DFT Study of the Structures of Au_x Clusters on a CeO₂(111) Surface