Modeling of temporally complex breathing patterns during Pd-catalyzed CO oxidation

Nekhamkina, Olga; Digilov, Rafael M.; Sheintuch, Moshe

doi:10.1063/1.1584651

Cited by 27 publications

(23 citation statements)

References 35 publications

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“…In figure 4 the dependencies of the average CO and oxygen coverages as the functions of p CO are shown for three different cases -for a pure surface without any impurities, for the surface with fast impurities when their concentration θ d on the surface is constant, θ d = 0.1, and for the surface with slow impurities, the concentration of which is determined by kinetic equation (13). The sticking coefficients s CO , s O are constants for all three cases and have the following values: s CO = 0.9 and s O = 0.06.…”

Section: Phase Diagrams Of the Modelmentioning

confidence: 99%

“…To analyse the system of kinetic equations (11)- (13) it is convenient to rewrite it in dimensionless form:…”

Section: Analysis Of the Kinetic Equationsmentioning

confidence: 99%

“…An attempt to investigate the effect of impurity atoms on one of the catalytic reactions, namely the reaction of catalytic CO oxidation on Pt surface [8][9][10][11][12][13][14], is made in the paper. Specifically, our purpose is to take into account the effect of equilibrium impurities with fast and slow self-dynamics on the reaction within the lattice-gas model with interactions on a surface.…”

Section: Introductionmentioning

confidence: 99%

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Effect of adsorbed impurities on catalytic CO oxidation

Bzovska¹,

Mryglod²

2009

Condens. Matter Phys.

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The effect of inactive adsorbed impurities on kinetics of catalytic synthesis of carbon dioxide is investigated in the framework of the lattice-gas model. Namely, two cases of equilibrium impurities with fast, compared with the reaction's rate, and slow self dynamics are analyzed. It is revealed that the adsorbed impurities shift the phase diagram to the region of lower temperatures and higher pressures p CO . In the case of slow impurities the bistable region is narrowed far more than in the case when their dynamics is fast and their distribution on the surface can be assumed to be equilibrium. The critical concentration of impurities at which the bistable region disappears, is found. From analysis of the kinetic equations the condition of the existence of the bifurcation region is analytically obtained.

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Section: Phase Diagrams Of the Modelmentioning

confidence: 99%

“…To analyse the system of kinetic equations (11)- (13) it is convenient to rewrite it in dimensionless form:…”

Section: Analysis Of the Kinetic Equationsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Effect of adsorbed impurities on catalytic CO oxidation

Bzovska¹,

Mryglod²

2009

Condens. Matter Phys.

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“…So, the oxidation of CO on platinum is known to proceed via the classical Langmuir-Hinshelwood (LH) mechanism (see [10][11][12]…”

mentioning

confidence: 99%

“…We will study the more open Pt(110) plane where the oscillatory behavior in the catalytic CO oxidation can be experimentally observed [8,9]. So, the oxidation of CO on platinum is known to proceed via the classical Langmuir-Hinshelwood (LH) mechanism (see [10][11][12](1) Here * denotes an empty site, adsorbed species are written with the subscript ads. CO 2 desorbs immediately at the temperatures under consideration and therefore constitutes an inert product.…”

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confidence: 99%

Chemical oscillations in catalytic CO oxidation reaction

Bzovska¹,

Mryglod²

2010

Condens. Matter Phys.

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Temporal dynamics of a heterogeneous catalytic system, namely of the catalytic CO oxidation on Pt(110) surface at low pressures, is investigated with taking into account the adsorbate-driven structural transformations of the catalyst surface. Uniform temporal periodic chemical oscillations of the CO and oxygen coverages, and the fraction of the surface of the 1 × 1 structure are obtained in a narrow region of phase diagram between two uniform stable states of high and low catalytic activities, respectively. Since Langmuir's pioneering studies, the oxidation of CO over Pt is a classical example of a heterogeneous catalytic reaction. It is considered to be generic due to its apparently simple mechanism, richness of spatio-temporal behavior, and practical relevance [1]. In particular, the temporal behavior of the reaction, for given constant control parameters, may either be constant (including bistability) or may become oscillatory or even chaotic [2,3]. First kinetic oscillations in this reaction were found by Hugo in 1970 on a supported catalyst. Later on, this phenomenon was also observed for other types of catalysts (polycrystalline wires and single crystals) both at ultrahigh vacuum (UHV) and subatmospheric conditions.Based on the knowledge about individual steps forming the reaction mechanism, temporal dynamics (with the exception of chaotic kinetics) could be successfully modelled by the solution of sets of ordinary differential equations (ODE's) for the variables describing the surface concentrations of the species involved [4][5][6]. For a close-packed Pt(111) surface, these are the coverages for adsorbed CO and O, respectively [7]. We will study the more open Pt(110) plane where the oscillatory behavior in the catalytic CO oxidation can be experimentally observed [8,9]. So, the oxidation of CO on platinum is known to proceed via the classical Langmuir-Hinshelwood (LH) mechanism (see [10][11][12](1) Here * denotes an empty site, adsorbed species are written with the subscript ads. CO 2 desorbs immediately at the temperatures under consideration and therefore constitutes an inert product. The other gases exhibit only small variations of their partial pressure under the applied conditions so that they can be assumed constant.Mathematical modelling of the experiments is conducted using a realistic model of catalytic CO oxidation on Pt(110) first studied by Krischer et al. [13]. The model takes into account adsorption of CO and oxygen molecules, reaction and desorption of CO molecules. For simplicity, surface diffusion of adsorbed CO molecules, surface roughening, faceting, formation of subsurface oxygen, and the effects of internal gas-phase coupling are not taken into account. The system of differential c I.S. Bzovska, I.M. Mryglod

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