Dimer Production in a Poisoned Catalytic Model

Schmidt, Daniel; Santos, M.

doi:10.1002/1521-396x(200109)187:1<305::aid-pssa305>3.0.co;2-x

Cited by 4 publications

(4 citation statements)

References 13 publications

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“…Our approach is based on the Ziff, Gulari and Barshad model (ZGB model) [11] for the irreversible oxidation of carbon monoxide on a catalytic surface. Besides, as the gaseous reservoir contain three types of molecules (O 2 , NH 3 and NO), we also used the ideas proposed by Schmidt and Santos [12] to study the poisoning of a catalytic surface when a third nonreactive monomer is present in the gaseous reservoir.…”

Section: Introductionsupporting

confidence: 73%

Numerical simulation of the kinetics of the selective catalytic reduction of NO by NH3

Bodanese

Santos²

2004

Braz. J. Phys.

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In this work we study a model of a catalytic reaction among three monomers in order to understand the kinetics of the selective catalytic reduction of NO by ammonia (4NO + 4NH3 + O2 → 4N2 + 6H2O). Our model takes into account the formation of the intermediate species in the global scheme of the reaction. Using the Monte Carlo method we simulated the model on a square lattice and determined its phase diagram.

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Section: Introductionsupporting

confidence: 73%

Numerical simulation of the kinetics of the selective catalytic reduction of NO by NH3

Bodanese

Santos²

2004

Braz. J. Phys.

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“…Notice how the impurities act as a barrier between the CO and O sites, preventing them from reacting. It has been shown that, when CO and O are allowed to diffuse on the surface, there can be a moderate reaction rate, even in the case that the impurities do not desorb [21].…”

Section: Amentioning

confidence: 99%

“…Other authors have applied a similar approach. They found that the reaction window of the model shrinks with increasing contaminant concentration, and that the high-y transition changes from discrete to continuous [20][21][22]. Although some of these studies introduce the possibility that the impurities desorb from the surface, they do not analyze in detail the effects of the desorption.…”

Section: Introductionmentioning

confidence: 99%

Effects of inert species in the gas phase in a model for the catalytic oxidation of CO

Rikvold

2012

Phys. Rev. E

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We study by kinetic Monte Carlo simulations the catalytic oxidation of carbon monoxide on a surface in the presence of contaminants in the gas phase. The process is simulated by a Ziff-Gulari-Barshad (ZGB) model that has been modified to include the effect of the contaminants and to eliminate an unphysical oxygen poisoned phase at very low CO partial pressures. The impurities can adsorb and desorb on the surface but otherwise remain inert. We find that if the impurities cannot desorb, no matter how small their proportion in the gas mixture, the reactive window and discontinuous transition to a CO poisoned phase at high CO pressures that characterize the original ZGB model disappear. The coverages become continuous, and once the surface has reached a steady state there is no production of CO(2). This is quite different from the behavior of systems in which the surface presents a fixed percentage of impurities. When the contaminants are allowed to desorb, the reactive phase appears again for CO pressures below a value that depends on the proportion of contaminants in the gas and on their desorption rate.

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“…Most of these models assume that the impurities are present in different concentrations on the catalytic surface. In this work we analyze the problem in a more realistic way by assuming that the impurities are part of the gas mixture [44][45][46]. The impurities can be adsorbed or desorbed, but otherwise they do not take part in the reaction.…”

Section: Introductionmentioning

confidence: 99%

Model for the catalytic oxidation of CO, including gas-phase impurities and CO desorption

Rikvold

2013

Phys. Rev. E

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We present results of kinetic Monte Carlo simulations of a modified Ziff-Gulari-Barshad model for the reaction CO+O → CO2 on a catalytic surface. Our model includes impurities in the gas phase, CO desorption, and a modification known to eliminate the unphysical O poisoned phase. The impurities can adsorb and desorb on the surface, but otherwise remain inert. In a previous work that did not include CO desorption [G. M. Buendía and P. A. Rikvold, Phys. Rev. E, 85 031143 (2012)], we found that the impurities have very distinctive effects on the phase diagram and greatly diminish the reactivity of the system. If the impurities do not desorb, once the system reaches a stationary state, the CO2 production disappears. When the impurities are allowed to desorb, there are regions where the CO2 reaction window reappears, although greatly reduced. Following experimental evidence that indicates that temperature effects are crucial in many catalytic processes, here we further analyze these effects by including a CO desorption rate. We find that the CO desorption has the effect to smooth the transition between the reactive and the CO rich phase, and most importantly it can counteract the negative effects of the presence of impurities by widening the reactive window such that now the system remains catalytically active in the whole range of CO pressures.

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Dimer Production in a Poisoned Catalytic Model

Cited by 4 publications

References 13 publications

Numerical simulation of the kinetics of the selective catalytic reduction of NO by NH3

Numerical simulation of the kinetics of the selective catalytic reduction of NO by NH3

Effects of inert species in the gas phase in a model for the catalytic oxidation of CO

Model for the catalytic oxidation of CO, including gas-phase impurities and CO desorption

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