Multilayer Adsorption of Interacting Polyatomics on Heterogeneous Surfaces

TL;DR

This paper introduces a generalized lattice-gas model for multilayer adsorption of interacting polyatomics on heterogeneous surfaces, deriving a new theoretical isotherm and analyzing its accuracy compared to Monte Carlo simulations.

Contribution

It presents a novel theoretical isotherm for multilayer adsorption of polyatomics on heterogeneous surfaces, extending the BET model with improved accuracy.

Findings

BET equation underestimates monolayer capacity

Heterogeneous surfaces and attractive interactions show compensation effects

The new model aligns well with Monte Carlo simulation results

Abstract

In the present work we introduce a generalized lattice-gas model to study the multilayer adsorption of interacting polyatomics on heterogeneous surfaces. Using an approximation in the spirit of the well-known Brunauer--Emmet--Teller (BET) model, a new theoretical isotherm is obtained in one- and two-dimensional lattices and compared with Monte Carlo simulation. In addition, we use the BET approach to analyze these isotherms and to estimate the monolayer volume. In all cases, we found that the use of the BET equation leads to an underestimate of the true monolayer capacity. However, significant compensation effects were observed for heterogeneous surfaces and attractive lateral interactions.