Adsorption of binary mixtures on heterogeneous surfaces

摘要

The adsorption of binary mixtures on heterogeneous surfaces is studied by computer simulation. The process is monitored by following the partial and total adsorption isotherms, adsorption energies, coverage fluctuations and differential heat of adsorption. These quantities are calculated by using Grand Canonical Monte Carlo simulation. Heterogeneous surfaces are represented by two kinds of sites, the so-called bivariate surface. Deep and shallow sites with energies epsilon _s and epsilon _D form l x l patches distributed at random or in a chessboard-like ordered domains on two-dimensional square lattices. The partial and total isotherms, as well as other thermodynamic quantities are very sensitive to the surface energy topography, particularly, when repulsive lateral interactions between adsorbed molecules are present.