Catalytic activity of Pd ensembles over Au(111) surface for CO oxidation: A first-principles study

Yuan, Dingwang; Chen, J. H.

doi:10.1063/1.3551617

Cited by 29 publications

(20 citation statements)

References 58 publications

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“…Further, other reaction energy barriers can be listed as follows: Pd1 (0.62 eV) and Pdsn (0.96 eV). These data illustrate that separate Pd monomer and continuous Pdnn geometries have high catalytic activity to the CO oxidation, which is consistent with the result of different congurations on Pd-Au(111) calculated by Yuan et al 23 It can be seen that the energy barrier of elementary steps is not high and the adsorption energy of product CO 2 in different conguration surfaces is close to 0.15 eV, which is physical adsorption and easy to remove on the surface. For the CO oxidation reaction, the Pd-Au catalyst has excellent catalytic activity, which is consistent with the conclusion of the experiments.…”

Section: Co + O a / Cosupporting

confidence: 90%

DFT study on effect of CO on the system of acetoxylation of ethylene to vinyl acetate

Zhang

Gao

et al. 2014

RSC Adv.

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We report the competitive adsorption of CO, ethylene and acetate on a Pd-Au (100) surface in the reaction system of vinyl acetate synthesis with DFT method. The effect of CO on the catalytic performance of Pd-Au in the vinyl acetate system was also studied. Moreover, the method of reducing the content of CO in the industrial process and the reaction path of CO on the Pd-Au catalyst was investigated. Furthermore, the effect of CO on the acetoxylation of ethylene to vinyl acetate was reflected in two aspects. Firstly, the adsorption of CO on a Pd atom is more stable than that of ethylene, in which the adsorption of ethylene is blocked and the catalytic activity of the Pd-Au alloy decreases. Secondly, the Pd-Au alloy can catalyze the CO oxidation reaction.

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Section: Co + O a / Cosupporting

confidence: 90%

DFT study on effect of CO on the system of acetoxylation of ethylene to vinyl acetate

Zhang

Gao

et al. 2014

RSC Adv.

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“…The highly reactive sites for this reaction are edges of the particle placed near the oxide substrate. A similar mechanism for the CO oxidation reaction was proposed by Yuan and co-workers 56 Our analysis of the CO oxidation reaction excludes the association reaction mechanism over the Au− −Pd(100) surface where the rate determining step is found to be the change of adsorption configuration of molecular oxygen from t-b-t to end-on configuration in order to allow one of the two oxygen atoms interacting with the C atom of adsorbed CO. This result is explained by the fact that the end-on adsorption of O 2 on the (100) surface is not likely to occur.…”

Section: Association Mechanismsupporting

confidence: 80%

The effect of Pd ensemble structure on the O2 dissociation and CO oxidation mechanisms on Au—Pd(100) surface alloys

Oğuz

Mineva

Guesmi

2018

The Journal of Chemical Physics

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The reactivity of various Pd ensembles on the Au-Pd(100) alloy catalyst toward CO oxidation was investigated by using density functional theory (DFT). This study was prompted by the search for efficient catalysts operating at low temperature for the CO oxidation reaction that is of primary environmental importance. To this aim, we considered Pd modified Au(100) surfaces including Pd monomers, Pd dimers, second neighboring Pd atoms, and Pd chains in a comparative study of the minimum energy reaction pathways. The effect of dispersion interactions was included in the calculations of the O dissociation reaction pathway by using the DFT-D3 scheme. The addition of the dispersion interaction strongly improves the adsorption ability of O on the Au-Pd surface but does not affect the activation energy barriers of the Transitions States (TSs). As for O to dissociate, it is imperative that the TS has lower activation energy than the O desorption energy. DFT-D3 is found to favor, in some cases, O dissociation on configurations being identified from uncorrected DFT calculations as inactive. This is the case of the second neighboring Pd configuration for which uncorrected DFT predicts positive Gibbs free energy (ΔG) of the O adsorption, therefore an endergonic reaction. With the addition of D3 correction, ΔG becomes negative that reveals a spontaneous O adsorption. Among the investigated Au-Pd (100) ensembles, the Pd chain dissociates most easily O and highly stabilizes the dissociated O atoms; however, it has an inferior reactivity toward CO oxidation and CO formation. Indeed, CO strongly adsorbs on the palladium bridge sites and therefore poisoning the surface Pd chain. By contrast, the second neighboring Pd configuration that shows somewhat lower ability to dissociate O turns out to be more reactive in the CO formation step. These results evidence the complex effect of Pd ensembles on the CO oxidation reaction. Associative CO oxidation proceeds with high energy barriers on all the considered Pd ensembles and should be excluded, in agreement with experimental observations.

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“…Surface Pd atoms on Au–Pd nanoparticles are catalytic active sites. ,− They appear on surface sites when temperature and support effects are considered. At 700 K, the Pd core Au shell structure is not energetically favored as in 0 K. Au and Pd atomic distributions, with respect to the cluster center of mass for all cases at 700 K, are illustrated in Figure S3.…”

Section: Resultsmentioning

confidence: 99%

Structural Rearrangement of Au–Pd Nanoparticles under Reaction Conditions: An ab Initio Molecular Dynamics Study

Lee²,

Wang³

et al. 2017

ACS Nano

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The structure, composition, and atomic distribution of nanoalloys under operating conditions are of significant importance for their catalytic activity. In the present work, we use ab initio molecular dynamics simulations to understand the structural behavior of Au-Pd nanoalloys supported on rutile TiO under different conditions. We find that the Au-Pd structure is strongly dependent on the redox properties of the support, originating from strong metal-support interactions. Under reducing conditions, Pd atoms are inclined to move toward the metal/oxide interface, as indicated by a significant increase of Pd-Ti bonds. This could be attributed to the charge localization at the interface that leads to Coulomb attractions to positively charged Pd atoms. In contrast, under oxidizing conditions, Pd atoms would rather stay inside or on the exterior of the nanoparticle. Moreover, Pd atoms on the alloy surface can be stabilized by hydrogen adsorption, forming Pd-H bonds, which are stronger than Au-H bonds. Our work offers critical insights into the structure and redox properties of Au-Pd nanoalloy catalysts under working conditions.

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Catalytic activity of Pd ensembles over Au(111) surface for CO oxidation: A first-principles study

Cited by 29 publications

References 58 publications

DFT study on effect of CO on the system of acetoxylation of ethylene to vinyl acetate

DFT study on effect of CO on the system of acetoxylation of ethylene to vinyl acetate

The effect of Pd ensemble structure on the O2 dissociation and CO oxidation mechanisms on Au—Pd(100) surface alloys

Structural Rearrangement of Au–Pd Nanoparticles under Reaction Conditions: An ab Initio Molecular Dynamics Study

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