Influence of spatial distribution of active centers on the kinetics of model heterogeneous catalytic processes

Ćwiklik, Łukasz; Jagoda‐Cwiklik, Barbara; Frankowicz, Marek

doi:10.1016/j.susc.2004.09.008

Cited by 10 publications

(14 citation statements)

References 11 publications

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“…As noted above, the broader use of these terms follows a trend of some recent works [2,21,22,23,29,32].…”

Section: Resultsmentioning

confidence: 84%

“…The model geometry is equivalent to that of Ref. [32], but here we will obtain an analytic solution that facilitates the illustration of different possible outcomes. We will use scaling concepts to explain the model results, so that this framework can be extended to more complex models and applications to real systems, where numerical solutions are usually necessary.…”

Section: Introductionmentioning

confidence: 99%

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Effects of diffusion and particle size in a kinetic model of catalyzed reactions

Mattos¹,

Reis²

2009

Journal of Catalysis

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We study a model for unimolecular reaction in a supported catalyst including reactant diffusion and desorption, using analytical methods and scaling concepts. For rapid reactions, enhancing surface diffusion or increasing particle size favors the flux of reactants to the catalyst particles, which increases the turnover frequency (TOF). The reactant flux towards the support becomes dominant when the ratio of diffusion lengths in the catalyst and in the support exceeds a critical value. A peak in the TOF is obtained for temperature-dependent rates if desorption energy in the support (E d ) exceeds those of diffusion (ED) and reaction (Er). Significant dependence on particle size is observed when the gaps between those energies are small, with small particles giving higher TOF. Slow reactions (Er > E d ) give TOF monotonically increasing with temperature, with higher reactant losses in small particles. The scaling concepts can be extended to interpret experimental data and results of more complex models.

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“…As noted above, the broader use of these terms follows a trend of some recent works [2,21,22,23,29,32].…”

Section: Resultsmentioning

confidence: 84%

Section: Introductionmentioning

confidence: 99%

Effects of diffusion and particle size in a kinetic model of catalyzed reactions

Mattos¹,

Reis²

2009

Journal of Catalysis

View full text Add to dashboard Cite

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“…Let u i2 = s 2 θ i2 and u i1 = s 1 θ i1 (θ i1 , θ i2 ∈ (0, 1)) be concentrations of the active and inactive sites occupied by the adsorbed molecules of reactant A i at moment t. It is evident that functions u i1 and u i2 present density of particles of species A i S bound to sites of type i that are located at point x at moment t. Current advances in nanotechnology made it possible to produce nanopatterned surfaces with assumed geometric properties and to study their reactivity [9]. In Sect.…”

Section: The Pdes Modelmentioning

confidence: 99%

“…The bibliography of the current state of theoretical research of reactions with spillover effects include: (i) papers based on the Monte Carlo simulations technique [6,[8][9][10], (ii) numerical solving of mean-field models [11][12][13][14][15][16], and (iii) the analytical description of such effect [2,17]. In [9], the uni-molecular A → B and bimolecular 2 A → B reversible reactions occuring on the composite catalyst surface are studied.…”

Section: Introductionmentioning

confidence: 99%

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Three mean-field models for bimolecular reactions proceeding on planar supported catalysts

Skakauskas

Katauskis

2015

J Math Chem

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The kinetics of A 1 + A 2 → A 1 A 2 reaction on supported catalysts is investigated numerically using three phenomenological models. The first of them is based on PDEs and includes: the bulk diffusion of both reactants from a bounded vessel towards the adsorbent and the product bulk one into the same vessel, adsorption and desorption of molecules of both reactants, and surface diffusion of adsorbed particles described by the diffusion flux based on the particle jumping into a nearest vacant adsorption site. The second model based on the ODEs is derived by averaging of the first one. The third mixed model is based on the PDEs for the bulk diffusion of both reactants and ODEs for the adsorbates surface diffusion on the supported catalyst which is composed of the active in reaction catalyst particle and inactive support. All three models are solved numerically and their results are compared. Two distinct arrangements of the adsorption sites are used for numerical calculations: (i) concentrations of the adsorption sites of the catalyst particle and support are equal, (ii) the total amount of adsorption sites of the active and inactive in reaction surface parts are the same. Calculations are performed for the case where: (i) molecules of both reactants adsorb only on the support and (ii) particles of one reactant adsorb on the active part while molecules of the other one adsorb on the support. The influence of the surface diffusivity, jump rate constants of the escaped particles of both adsorbates via the catalyst-support interface, and size of the active catalyst particle (or size-dependent distribution of active sites in the second case of their arrangement) on the catalytic reactivity of the supported catalyst is studied.

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Numerical study of the kinetics of unimolecular heterogeneous reactions onto planar surfaces

Skakauskas

Katauskis

2011

J Math Chem

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Influence of spatial distribution of active centers on the kinetics of model heterogeneous catalytic processes

Cited by 10 publications

References 11 publications

Effects of diffusion and particle size in a kinetic model of catalyzed reactions

Effects of diffusion and particle size in a kinetic model of catalyzed reactions

Three mean-field models for bimolecular reactions proceeding on planar supported catalysts

Numerical study of the kinetics of unimolecular heterogeneous reactions onto planar surfaces

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