Nitrogen Monoxide Adsorption on Pt&lt;SUB&gt;4&lt;/SUB&gt; Clusters Coated on γ-Al&lt;SUB&gt;2&lt;/SUB&gt;O&lt;SUB&gt;3&lt;/SUB&gt; (111) Surface

Oemry, Ferensa; Escaño, Mary Clare Sison; Kishi, Hirofumi; Kunikata, Shinichi; Nakanishi, Hiroshi; Kasai, Hideaki; Maekawa, Hiroyoshi; Osumi, Kazuo; Tashiro, Yoshihisa

doi:10.1166/jnn.2011.3915

Cited by 13 publications

(12 citation statements)

References 22 publications

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“…The energy for atop adsorption on the distorted arrangement of Pd 4 (the only adsorption mode found for supported Pd 4 ) is -31.8 kcal mol -1 , in the midway between atop adsorptions on the tetrahedral and on the planar arrangements. Therefore, the preferential adsorption site is dependent on the arrangement of the Pd n cluster, as found in previous studies, 22,23,50 with palladium atoms having higher coordination number showing lower ability to accept the NO molecule.Adsorptions on the atop sites lead to Pd-N distances that are in general lower than the corresponding Pd-N distances for adsorption on the bridge or hollow sites, reflecting the lower coordination number of the adsorbed NO molecule. In any case, the adsorption occurs in a tilted orientation, with O-N-Pd angles between 113 and 136°.…”

supporting

confidence: 54%

supporting

confidence: 54%

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The Effect of Gamma-Al₂O₃Support on the NO Adsorption on Pd₄Cluster

Prates¹,

Ferreira²,

Carneiro³

et al. 2016

Journal of the Brazilian Chemical Society

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The effect of γ-Al 2 O 3 support on the NO adsorption on Pd 4 clusters was investigated by means of density functional theory (DFT) calculations. Pd 4 adsorbed on γ-Al 2 O 3 (represented by a Al 14 O 24 H 6 cluster) changes its preferential geometry from tetrahedral to a distorted planar structure. The alumina support promotes a higher dispersion in the palladium catalyst and reduces the NO adsorption energy to -25.6 kcal mol -1 (computed at B3LYP/LANL2DZ/6-311+G(d)), in close agreement with the experimental value of -27.2 kcal mol . Charge density analysis show that the electron flux between the NO molecule and Pd 4 depends on the adsorption form, with back-donation being stronger in the bridge adsorption mode.Keywords: Pd clusters, DFT, supported-Pd clusters, alumina, NO adsorption, back-donation IntroductionPalladium catalysts have found wide appllication in several areas of chemistry. [1][2][3] One of the most common and established use of palladium catalyst is to control automobile exhaust gas emission. [4][5][6] Use of catalytic converter in automobile exhaust is a requirement to reach the recommended limits for emission of toxic byproducts. Although studies have been dedicated to the understanding of the catalytic conversion process in the exhaust emission, 7 more fundamental studies are still necessary for a full comprehension of the catalytic process, particularly at the molecular level. 8,9 Commonly, the platinum and palladium catalysts are supported on metal oxides, among them γ-Al 2 O 3 , although oxides of cerium, zirconium and titanium are also frequently employed. [10][11][12] These supported catalysts are thus employed to remove carbon monoxide (CO), nitric oxide (NO), NO x and SO x contaminants, among others, from the exhaust engine. [4][5][6] Nitric oxide has an odd number of electrons and is one of the most versatile molecules, making its chemistry and adsorption process of particular interest. 13 The adsorption of NO on the supported catalyst surface has been investigated by both experimental 7,14-20 and theoretical procedures. [21][22][23][24][25][26][27][28][29] NO adsorbs on small Pd clusters through its nitrogen atom in a tilted orientation, preferentially in the hcp threefold and bridge sites, 27 although the relative binding energies are strongly dependent on the size and geometry of the cluster employed. 27 For adsorption of NO on an extended surface at low coverage the interaction is determined by electron donation and back-donation involving the 5σ/2π* antibonding orbital of the NO molecule and the d-bands of the transition metal, with a net charge transfer from the transition metal to the adsorbed NO. 29 However, the extent of the interaction via the back-donation process is strongly dependent on the coordination mode of the NO molecule. On a flat surface, the preferential adsorption occurs on a hollow-site. 29 Adsorption on the energetically less favorable top-site results in tilted orientation with the NO bent to the metal surface.In the vast literature on theoretical studies of N...

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confidence: 54%

supporting

confidence: 54%

The Effect of Gamma-Al₂O₃Support on the NO Adsorption on Pd₄Cluster

Prates¹,

Ferreira²,

Carneiro³

et al. 2016

Journal of the Brazilian Chemical Society

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“…Understanding the reduction process of NO x on surfaces to form less hazardous gases is of utmost importance and consequently has been widely studied. [1][2][3][4][5][6][7][8][9] Generally, the process involves the dissociation of the molecule with the aid of a catalyst to form other less harmful gases. Due to the large amount of energy required to break the N-O bond, NO dissociation is the rate-limiting step.…”

Section: Introductionmentioning

confidence: 99%

A density functional theory-based study on the dissociation of NO on a CuO(110) surface

Moreno¹,

Padama²,

Kasai³

2014

CrystEngComm

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“…The Pt-Al 2 O 3 slab was then hydroxylated at the same concentration of 0.25 mL. We chose the high-symmetry Pt 4 cluster as a model catalyst since it exhibits a high stability function and provides 3-dimensional active sites for catalysis with efficient computational cost. , The Pt 4 cluster has been used in several catalysis studies. ,, …”

Section: Models and Methodsmentioning

confidence: 99%

Enhancing Kinetics of Carbonyl Sulfide Hydrolysis Using Pt-Supported Al₂O₃ Catalysts: First-Principles-Informed Energetic Span Analysis

et al. 2023

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Catalytic hydrolysis is considered an effective strategy for treating carbonyl sulfide (COS)�a toxic sulfurcontaining gas that causes problems to the environment and petrochemical industries. Al 2 O 3 -based materials are commonly used as catalysts for COS hydrolysis owing to their stability and cost effectiveness. However, they still suffer from sulfur poisoning leading to partial COS conversion after long time use. To improve their catalytic performances, herein, we computationally designed and studied the catalytic activity of the Pt-supported Al 2 O 3 catalysts by means of density functional calculations. We mechanistically explored the COS hydrolysis on both bare and Pt-decorated surfaces to reveal the role of Pt catalysts in the reaction kinetics. We find that bare Al 2 O 3 suffers from difficult C− S bond breaking as its barrier is relatively high. Pt facilitates C−S bond breaking where its barrier is reduced by more than half (1.34 to 0.60 eV). However, the Pt−Al 2 O 3 catalyst could encounter sulfur poisoning as the sulfur-containing intermediates are rather stable. Such issues could be remedied by increasing the operating temperature to destabilize the intermediates and promote product desorption. The energetic span models reveal that the important states of bare and Pt−Al 2 O 3 are indeed C−S bond breaking and product desorption corresponding to an energy span of 2.72 and 1.67 eV at 773 K, respectively�suggesting that Pt dramatically enhances the catalytic activity of Al 2 O 3 -based catalysts toward COS hydrolysis. The suggested operating temperatures are above 673 K to avoid sulfur poisoning. Our findings will be useful for the development of more efficient Al 2 O 3 -based catalysts for treating COS.

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Nitrogen Monoxide Adsorption on Pt<SUB>4</SUB> Clusters Coated on γ-Al<SUB>2</SUB>O<SUB>3</SUB> (111) Surface

Cited by 13 publications

References 22 publications

The Effect of Gamma-Al₂O₃Support on the NO Adsorption on Pd₄Cluster

The Effect of Gamma-Al₂O₃Support on the NO Adsorption on Pd₄Cluster

A density functional theory-based study on the dissociation of NO on a CuO(110) surface

Enhancing Kinetics of Carbonyl Sulfide Hydrolysis Using Pt-Supported Al₂O₃ Catalysts: First-Principles-Informed Energetic Span Analysis

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Nitrogen Monoxide Adsorption on Pt<SUB>4</SUB> Clusters Coated on γ-Al<SUB>2</SUB>O<SUB>3</SUB> (111) Surface

Cited by 13 publications

References 22 publications

The Effect of Gamma-Al2O3Support on the NO Adsorption on Pd4Cluster

The Effect of Gamma-Al2O3Support on the NO Adsorption on Pd4Cluster

A density functional theory-based study on the dissociation of NO on a CuO(110) surface

Enhancing Kinetics of Carbonyl Sulfide Hydrolysis Using Pt-Supported Al2O3 Catalysts: First-Principles-Informed Energetic Span Analysis

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Product

Resources

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The Effect of Gamma-Al₂O₃Support on the NO Adsorption on Pd₄Cluster

The Effect of Gamma-Al₂O₃Support on the NO Adsorption on Pd₄Cluster

Enhancing Kinetics of Carbonyl Sulfide Hydrolysis Using Pt-Supported Al₂O₃ Catalysts: First-Principles-Informed Energetic Span Analysis