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

Bodanese, J. P.; Santos, M.

doi:10.1590/s0103-97332004000300019

Cited by 2 publications

(1 citation statement)

References 14 publications

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“…As for lattice models, the main focus has been on simulations, principally Monte Carlo studies on planar lattices. Effects of catalytic poisoning for specific reactions have been explored by designing algorithms, some general enough to account for "feedback" between surface concentration and absorption rate [5][6][7].…”

Section: Introductionmentioning

confidence: 99%

Competing reaction processes on a lattice as a paradigm for catalyst deactivation

Abad

Kozak

2015

Phys. Rev. E

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We mobilize both a generating function approach and the theory of finite Markov processes to compute the probability of irreversible absorption of a randomly diffusing species on a lattice with competing reaction centers. We consider an N-site lattice populated by a single deep trap, and N − 1 partially absorbing traps (absorption probability 0 < s < 1). The influence of competing reaction centers on the probability of reaction at a target site (the deep trap) and the mean walk length of the random walker before localization (a measure of the reaction efficiency) are computed for different geometries. Both analytic expressions and numerical results are given for reactive processes on two-dimensional surfaces of Euler characteristic = 0 and = 2. The results obtained allow a characterization of catalyst deactivation processes on planar surfaces and on catalyst pellets where only a single catalytic site remains fully active (deep trap), the other sites being only partially active as a result of surface poisoning. The central result of our study is that the predicted dependence of the reaction efficiency on system size N and on s is in qualitative accord with previously reported experimental results, notably catalysts exhibiting selective poisoning due to surface sites that have different affinities for chemisorption of the poisoning agent (e.g., acid zeolite catalysts). Deviations from the efficiency of a catalyst with identical sites are quantified, and we find that such deviations display a significant dependence on the topological details of the surface (for fixed values of N and s we find markedly different results for, say, a planar surface and for the polyhedral surface of a catalyst pellet). Our results highlight the importance of surface topology for the efficiency of catalytic conversion processes on inhomogeneous substrates, and in particular for those aimed at industrial applications. From our exact analysis we extract results for the two limiting cases s ≈ 1 and s ≈ 0, corresponding respectively to weak and strong catalyst poisoning (decreasing s leads to a monotonic decrease in the efficiency of catalytic conversion). The results for the s ≈ 0 case are relevant for the dual problem of light-energy conversion via trapping of excitations in the chlorophyll antenna network. Here, decreasing the probability of excitation trapping s at sites other than the target molecule does not result in a decrease of the efficiency as in the catalyst case, but rather in enhanced efficiency of light-energy conversion, which we characterize in terms of N and s. The one-dimensional case and its connection with a modified version of the gambler's ruin problem are discussed. Finally, generalizations of our model are described briefly.

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Section: Introductionmentioning

confidence: 99%

Competing reaction processes on a lattice as a paradigm for catalyst deactivation

Abad

Kozak

2015

Phys. Rev. E

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Mean field approximation for the kinetics of the selective catalytic reduction of NO by ammonia

Santos

Bodanese

Grandi

2007

Physica Status Solidi (a)

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In this work we study a catalytic reaction model among three monomers in order to understand the chemical kinetics of the selective catalytic reduction of nitrogen oxide 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. In order to determine the dynamical behaviour of the model we used single site approximation method. In this approach we have observed that, depending on the values of the control parameters, the model presents an active or an inactive phase. In fact, the dynamical phase diagram of the model exhibits a first order line separating these two phases. (© 2007 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)

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

Cited by 2 publications

References 14 publications

Competing reaction processes on a lattice as a paradigm for catalyst deactivation

Competing reaction processes on a lattice as a paradigm for catalyst deactivation

Mean field approximation for the kinetics of the selective catalytic reduction of NO by ammonia

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