Molecular simulation of gas adsorption in realistic models of silica nanopores

This paper presents a molecular simulation study of Xe adsorption at 195 K in two atomistic models of silica MCM-41 pores. Model A consists of a regular cylindrical pore having a constant section. Model B has an important surface disorder that reproduces the morphological features of an on-lattice simulation mimicking the synthesis process of MCM-41 pores. The adsorption isotherm for model A exhibits a large hysteresis loop that is typical of capillary condensation in regular nanopores. In contrast, the adsorption/desorption process for model B is a quasi-continuous and quasi-reversible mechanism. Due to the important surface roughness for model B, the isosteric heat of adsorption for this sample is much larger than that for the regular cylindrical pore. Where possible, comparison with experimental data is made.