1) constructed under the premises of the dual sitebond model have been used as probe substrates to study the effects of variable connectivity and pore-size correlation on the aspects of both hysteresis loops and primary sorption scanning curves. The shapes of the hysteresis loops obtained from sorption simulation in networks of diverse morphologies are compared and discussed. It is found that the precursor structural parameters of the Monte Carlo simulated networks together with the sorption algorithm used in this work, can lead to IUPAC types H1, H2 and H3-like hysteresis loops, depending on the values chosen for the pore-size distribution parameters and mean connectivity. Network morphology also influences greatly the mechanisms of sorption processes in poorly or highly size correlated porous substrates. Sorption results on these 3-D porous specimens help to visualize the extents of pore blocking (vapour percolation) and delayed adsorption (liquid percolation) phenomena and also to foresee the most appropriate methods to ascertain the structure of porous materials.

No abstract

No abstract

No abstract

Menisci interactions can strongly affect the development of adsorption processes in mesoporous materials. Phenomena such as delayed and advanced adsorption represent outright manifestations of these interactions then leading to deceptive determinations of the pore-size distribution. At present, a characterization study involving simulated porous networks with qualities similar to those owned by real materials and in which the above processes can occur is still lacking. A Monte Carlo procedure is used to evaluate the extent of delayed and advanced adsorption in porous structures of assorted morphologies. This treatment allows a clear detection of the types of mesoporous structures that can experience the incidence of delayed and advanced adsorption.

No abstract

The description of disordered porous media through the Dual Site‐Bond Model (DSBM) is reviewed and updated with the inclusion of new results. After a brief discussion of the DSBM, the percolation properties of networks are studied. These present novel features with respect to classical percolation in non‐correlated networks. These properties are then used in discussing different processes in disordered porous media, namely, invasion percolation and adsorption‐desorption hysteresis. Finally, a method for the characterization of pore size distributions from experimental adsorption‐desorption isotherms is proposed.

Kinetic oscillations in the catalytic reduction of NO by CO on a reconstructing Pt(100) surface are simulated by using a dynamic Monte Carlo method. The simulation is based on the HS model and takes into account an alternative reaction mechanism arising from recent experimental findings for the catalytic reduction of No on Rh(111), which replaces the classical N+N recombination step by the formation of a (N-NO)(*) intermediary species for the production of molecular nitrogen. A synchronized mechanism and spatiotemporal patterns are observed during the oscillations. Oscillations are analyzed in terms of the controlling parameters involved in the reaction mechanism. Different values of these parameters lead to sustained, attenuated, and modulated oscillations.