Energetic Topography Effects on Mobile Adsorption on Heterogeneous Surfaces at Low Coverage

Langmuir ◽  
2003 ◽  
Vol 19 (17) ◽  
pp. 6737-6743 ◽  
Author(s):  
M. Nazzarro ◽  
G. Zgrablich
Keyword(s):  
Heterogeneous Surfaces ◽  
Adsorption On Heterogeneous Surfaces ◽  
Mobile Adsorption ◽  
Low Coverage

Adsorption on heterogeneous surfaces: Numerical analysis of models for the Dubinin-Radushkevich equation

1981 ◽  
Vol 46 (8) ◽  
pp. 1709-1721 ◽  
Author(s):  
Miloš Smutek ◽  
Arnošt Zukal
Keyword(s):  
Integral Equation ◽  
Numerical Analysis ◽  
Numerical Method ◽  
Adsorption Behaviour ◽  
Heterogeneous Surfaces ◽  
Strong Energy ◽  
Adsorption On Heterogeneous Surfaces ◽  
Heterogeneity Parameter ◽  
Adsorption Energies ◽  
Mobile Adsorption

A numerical method, based on the integral equation of the adsorption on energy heterogeneous surfaces, is suggested for the evaluation of overall isotherm. It is shown that for the distribution of adsorption energies given by Eq. (1.11) and different models of the adsorption behaviour, the overall isotherms obey approximately the Dubinin-Radushkevich equation. The strong energy heterogeneity smears effectively the differences between the localized and mobile adsorption and leads to the same character of the overall isotherm with only a slightly changed heterogeneity parameter.

scholarly journals Energetic Topography in Adsorption onto Heterogeneous Surfaces

2007 ◽  
Vol 25 (6) ◽  
pp. 365-384
Author(s):  
A.J. Ramirez-Pastor ◽  
F. Bulnes ◽  
M. Nazzarro ◽  
J.L. Riccardo ◽  
G. Zgrablich
Keyword(s):  
Monte Carlo ◽  
Gaussian Model ◽  
Power Laws ◽  
Crystalline Solid ◽  
Heterogeneous Surfaces ◽  
Spatial Correlation Function ◽  
Basic Ideas ◽  
Strip Geometry ◽  
Mobile Adsorption ◽  
Low Coverage

The adsorption of gases onto heterogeneous surfaces has been reviewed, highlighting models capable of taking energetic topography effects into account. The basic ideas are contained in the fundamental Generalized Gaussian Model (GGM) developed to represent mobile adsorption onto heterogeneous surfaces at low coverage, where the energetic topography is considered through an adsorptive energy distribution with a spatial correlation function. Adsorbate molecules interact amongst them via Lennard-Jones interactions. Model predictions have been compared to Monte Carlo simulations of adsorption onto heterogeneous solids obtained by doping a pure crystalline solid with different concentrations of impurities. Energetic topography effects were shown to be important, being predicted correctly by the model at low coverage. In addition, a simplified patchwise model was also considered. The adsorption of particles with nearest-neighbour attractive and repulsive interactions was studied using Monte Carlo simulation on bivariant surfaces characterized by patches of weak and strong adsorbing sites of size “i”. Patches were considered to have either a square or a strip geometry, arranged either in a deterministic ordered structure or in a random way. Quantities have been identified which scale obeying power laws as a function of the scale length “l”. The consequences of this finding for the determination of the energetic topography of a surface from adsorption measurements were discussed.

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