CO oxidation on Pd(100): A study of the coadsorption of oxygen and carbon monoxide

Stuve, Eric M.; Madix, Robert J.; Brundle, C. R.

doi:10.1016/0039-6028(84)90235-8

Cited by 214 publications

(131 citation statements)

References 35 publications

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“…The C 1s XP spectra show a primary feature centered at 285.5 eV for various coverages of CO (as shown in the lower panel of figure 5), which is in excellent agreement with the observations by Jones et al [23,24]. Madix et al [25], have reported that the saturation coverage for CO on Pd(100) at room temperature is 0.53 ML. By comparing the peak area of the C 1s is [19] and acetic acid [26] to be approximately 1.5 ML.…”

Section: Xpssupporting

confidence: 89%

Kinetic and Spectroscopic Studies of Vinyl Acetate Synthesis Over Pd(100)

et al. 2006

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A kinetic study of vinyl acetate (VA) synthesis over a Pd(100) catalyst is described, and the effect of particle-size on this reaction ascertained by comparing the single crystal data with data from supported Pd catalysts (5 wt% Pd/SiO 2 , d Pd =4.2 nm, and 1 wt% Pd/SiO 2 , d Pd =2.5 nm). A negative reaction order with respect to ethylene and a positive order with respect to oxygen were found for the model and supported catalytic systems, whereas the catalytic stability was strongly dependent on the particle size. The mechanism for VA synthesis is proposed to be identical on all catalysts studied based on the similarities of the kinetic parameters. Carbon-containing species on the poisoned Pd(100) catalyst were investigated by X-ray photoelectron spectroscopy (XPS), and the coverage was estimated to be approximately 1.5 ML after VA synthesis.KEY WORDS: kinetics of vinyl acehate synthesis; Pd(100) catalysts.

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Section: Xpssupporting

confidence: 89%

Kinetic and Spectroscopic Studies of Vinyl Acetate Synthesis Over Pd(100)

et al. 2006

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“…Since in this system higher oxygen coverages above Θ ∼ 0.5 monolayers [ML, defined with respect to the number of Pd atoms in one layer of Pd(100)] induce structures containing incorporated oxygen 14,15,16,17,18 , we concentrate on the low coverage regime. For this regime, two ordered structures have hitherto been characterized experimentally 14,15,16,17,19,20 : A p(2 × 2)-O structure at 0.25 ML and a c(2 × 2)-O structure at 0.5 ML, both with O adsorbed in the on-surface fourfold hollow sites. The material science motivation of our firstprinciples LGH study is then to extract the lateral interactions operating between the adsorbed O atoms at the surface and to study the ordering behavior they imply.…”

Section: 345mentioning

confidence: 99%

Accuracy of first-principles lateral interactions: Oxygen at Pd(100)

2007

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We employ a first-principles lattice-gas Hamiltonian (LGH) approach to determine the lateral interactions between O atoms adsorbed on the Pd(100) surface. With these interactions we obtain an ordering behavior at low coverage that is in quantitative agreement with experimental data. Uncertainties in the approach arise from the finite LGH expansion and from the approximate exchange-correlation (xc) functional underlying the employed density-functional theory energetics. We carefully scrutinize these uncertainties and conclude that they primarily affect the on-site energy, which rationalizes the agreement with the experimental critical temperatures for the order-disorder transition. We also investigate the validity of the frequently applied assumption that the ordering energies can be represented by a sum of pair terms. Restricting our LGH expansion to just pairwise lateral interactions, we find that this results in effective interactions which contain spurious contributions that are of equal size, if not larger than any of the uncertainties e.g. due to the approximate xc functional.

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“…The following dynamical processes are included in our reaction model: nonactivated adsorption of CO͑gas͒ on single empty sites of any type at rate P CO ͑in unit of ML/s͒; nonactivated dissociative adsorption of O 2 ͑gas͒ on diagonally adjacent empty 4fh sites, provided that the six adjacent neighbors are free of O͑ads͒ ͑the eight-site rule 10,14,19,25,26 ͒ at rate P O 2 ͑ML/s͒; activated desorption of CO with barrier determined by the total adsorption energy ͑desorption of oxygen is effectively inoperative under typical reaction conditions͒; reaction to form CO 2 ͑gas͒ of CO͑ads͒-O͑ads͒ pairs with a barrier of 0.73 eV ͑0.95 eV͒ for pairs separated by a ͑by ͱ 5a / 2 and ͱ 2a͒, where these barriers are based on DFT analysis 27 and comparison with experimental temperatureprogramed-reaction ͑TPR͒ spectra; 28 and diffusive hopping of both CO͑ads͒ and O͑ads͒ as described below.…”

Section: Lattice-gas Model For Co Oxidation On Pd"100…mentioning

confidence: 99%

Chemical diffusion of CO in mixed CO+O adlayers and reaction-front propagation in CO oxidation on Pd(100)

Liu

Evans

2006

The Journal of Chemical Physics

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Within the framework of a realistic atomistic lattice-gas model, we present the theoretical formulation and simulation procedures for precise analysis of the chemical diffusion flux of highly mobile CO within a nonuniform interacting mixed CO+O adlayer on a Pd(100) surface. The approach applies in both regimes of relatively immobile unequilibrated and fairly mobile near-equilibrated O adlayer distributions. Spatiotemporal behavior in surface reactions is controlled by chemical diffusion in mixed adlayers. Thus, we naturally integrate the above analysis with a previously developed multiscale modeling strategy to describe mesoscale reaction front propagation in CO oxidation on Pd(100). This treatment avoids using a simplified prescription of chemical diffusion and reaction kinetics as in traditional mean-field reaction-diffusion equation approaches. KeywordsAtomistic lattice-gas model, chemical diffusion flux, reaction-diffusion equation, reaction-front propagation, computer simulation, diffusion in gases, oxidation, palladum, reaction kinetics, surface reactions, carbon monoxide Within the framework of a realistic atomistic lattice-gas model, we present the theoretical formulation and simulation procedures for precise analysis of the chemical diffusion flux of highly mobile CO within a nonuniform interacting mixed CO+O adlayer on a Pd͑100͒ surface. The approach applies in both regimes of relatively immobile unequilibrated and fairly mobile near-equilibrated O adlayer distributions. Spatiotemporal behavior in surface reactions is controlled by chemical diffusion in mixed adlayers. Thus, we naturally integrate the above analysis with a previously developed multiscale modeling strategy to describe mesoscale reaction front propagation in CO oxidation on Pd͑100͒. This treatment avoids using a simplified prescription of chemical diffusion and reaction kinetics as in traditional mean-field reaction-diffusion equation approaches.

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CO oxidation on Pd(100): A study of the coadsorption of oxygen and carbon monoxide

Cited by 214 publications

References 35 publications

Kinetic and Spectroscopic Studies of Vinyl Acetate Synthesis Over Pd(100)

Kinetic and Spectroscopic Studies of Vinyl Acetate Synthesis Over Pd(100)

Accuracy of first-principles lateral interactions: Oxygen at Pd(100)

Chemical diffusion of CO in mixed CO+O adlayers and reaction-front propagation in CO oxidation on Pd(100)

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