CO oxidation on Pd(1 1 1), Pt(1 1 1), and Rh(1 1 1) surfaces studied by infrared chemiluminescence spectroscopy

Nakao, Kenji; Watanabe, Osamu; Sasaki, Toshiaki; Ito, Shin Ichi; Tomishige, Keiichi; Kunimori, Kimio

doi:10.1016/j.susc.2007.04.015

Cited by 19 publications

(17 citation statements)

References 18 publications

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“…[19][20][21][22][23][24][25][26][27][28] Formation of carbon deposits that usually reduce the catalyst activity has been extensively studied in the decomposition of ethylene, 7,15,16,29,30 methane 31 (using supersonic molecular beams), and benzene 18 by means of low-energy electron diffraction (LEED) 5,7,8,18,[32][33][34] andscanningtunnelingmicroscopy(STM)experiments; 15,16,18,29,[35][36][37][38][39][40][41] to a lesser extent, high-resolution electron-energy-loss spectroscopy (HREELS) 33,34 and Auger electron spectroscopy (AES) 6,8,18 have been applied. Many of these experiments indicate the formation of a graphitic overlayer, known as monolayer graphite (MG) or graphene, 7,8,[15][16][17][18]31,33,37,…”

Section: Introductionmentioning

confidence: 99%

Carbon on Platinum Substrates: From Carbidic to Graphitic Phases on the (111) Surface and on Nanoparticles

2009

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The formation of carbonaceous deposits on Pt(111) surfaces and Pt nanoparticles has been studied using suitable models and density-functional calculations. The study addresses a broad range of processes, from the very first stage of carbon deposition up to a final building of graphene monolayers (ML) defined as a 1:1 ratio of the number of C atoms to surface Pt atoms. A carbidic phase is formed below a coverage of approximately 0.3 ML, when negatively charged carbon atoms are strongly adsorbed preferentially on fcc hollow sites. On Pt nanoparticles, the adsorption of carbon atoms seems to be enhanced near particle edges due to the special flexibility of defect sites. Above a coverage of approximately 0.3 ML, the formation of small C(n) aggregates becomes possible. Interestingly, thermodynamics favors the formation of C(3) trimers at a coverage of 0.33 ML, whereas the formation of C(2) dimers requires a higher coverage of 0.5 ML. The covalently bonded C(2) species is supposed to be the key fragment for the formation of benzene-like rings at coverages above 0.6 ML. These rings are expected to be the building blocks for the graphene monolayer. However, the typical electronic structure of graphene is not observed until a coverage above approximately 1.8 ML is reached. We corroborated the experimentally suggested carbon double-layer to be stable. It is proposed to consist of a monolayer of carbidic atoms C adsorbed on Pt with a graphene layer adsorbed on the carbidic layer. Some of the carbidic atoms serve as anchors for the graphene layer, with noticeably strong covalent bonds formed. This double-layer model would imply a much higher adhesion of the graphene layer than in the single-layer model.

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Section: Introductionmentioning

confidence: 99%

Carbon on Platinum Substrates: From Carbidic to Graphitic Phases on the (111) Surface and on Nanoparticles

2009

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“…In catalysis, for example, understanding the adsorption mechanism of species on catalytic surfaces-mainly electrodes-is essential in order to formulate a design principle for the prefect catalyst that can reach the optimum efficiency for a desired electrochemical process [81][82][83]. Typically, the adsorption of CO on metal surface is widely acknowledged as the prototypical system for studying molecular chemisorption [84][85][86][87].…”

Section: Solving the Co Adsorption Puzzle With The U Correctionmentioning

confidence: 99%

The DFT+U: Approaches, Accuracy, and Applications

Tolba¹,

Gameel²,

Ali³

et al. 2018

Density Functional Calculations - Recent Progresses of Theory and Application

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This chapter introduces the Hubbard model and its applicability as a corrective tool for accurate modeling of the electronic properties of various classes of systems. The attainment of a correct description of electronic structure is critical for predicting further electronic-related properties, including intermolecular interactions and formation energies. The chapter begins with an introduction to the formulation of density functional theory (DFT) functionals, while addressing the origin of bandgap problem with correlated materials. Then, the corrective approaches proposed to solve the DFT bandgap problem are reviewed, while comparing them in terms of accuracy and computational cost. The Hubbard model will then offer a simple approach to correctly describe the behavior of highly correlated materials, known as the Mott insulators. Based on Hubbard model, DFT+U scheme is built, which is computationally convenient for accurate calculations of electronic structures. Later in this chapter, the computational and semiempirical methods of optimizing the value of the Coulomb interaction potential (U) are discussed, while evaluating the conditions under which it can be most predictive. The chapter focuses on highlighting the use of U to correct the description of the physical properties, by reviewing the results of case studies presented in literature for various classes of materials.

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“…To evaluate the state of Pd particles and Co species, IR spectra of adsorbed CO were measured. assignable to bridge-bonded CO on Pd [19,37,[55][56][57][58][59][60][61]. The band intensity was normalized with the sharp band at 2065 cm −1 .…”

Section: Catalystmentioning

confidence: 99%

Effect of preparation method of Co-promoted Pd/alumina for methane combustion

et al. 2015

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CO oxidation on Pd(1 1 1), Pt(1 1 1), and Rh(1 1 1) surfaces studied by infrared chemiluminescence spectroscopy

Abstract: The infrared (IR) chemiluminescence studies of CO 2 formed during steady-state CO oxidation over Pd(111), Pt(111), and Rh (111)

Cited by 19 publications

References 18 publications

Carbon on Platinum Substrates: From Carbidic to Graphitic Phases on the (111) Surface and on Nanoparticles

Carbon on Platinum Substrates: From Carbidic to Graphitic Phases on the (111) Surface and on Nanoparticles

The DFT+U: Approaches, Accuracy, and Applications

Effect of preparation method of Co-promoted Pd/alumina for methane combustion

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