Dimer physisorption on heterogeneous substrates

RAMIREZ-PASTOR, A.J.; NAZZARRO, M.S.; RICCARDO, J.L.; ZGRABLICH, G.

SURFACE SCIENCE

ELSEVIER SCIENCE BV

Año: 1995 vol. 341 p. 249 - 261

0039-6028

Physisorption of dimers on heterogeneous surfaces is studied by combining theoretical modelling, Monte Carlo simulation and experimental results. Monte Carlo simulation of dimer physisorption is carried out for substrates modelled in such a way that random, patchwise and intermediate adsorption site topographies can be generated. Simulated adsorption isotherms are used to test a model for adsorption of polyatomic molecules on heterogeneous surfaces, recently developed by Nitta et al.. Experimental adsorption isotherms for O2 and N2 adsorbed on zeolites 5A and 10X, as well as adsorption heats, are used to test the reliability of the simulation model. A simple theoretical form for the adsorption isotherm, based on the Fermi-Dirac approach, is finally proposed. Close agreement between simulated, theoretical and experimental results supports the validity of the proposed equation to describe interactions of diatomic gases with zeolites. © 1995 Elsevier Science B.V. All rights reserved.