A Simple Two-Dimensional NLDFT Model of Gas Adsorption in Finite Carbon Pores. Application to Pore Structure Analysis

In this work, we present a carbon slit pore model based on graphene sheet walls of finite dimensions. This is a two-dimensional modification of the widely used one-dimensional pore model that assumes graphite-like infinitely extended pore walls. This more realistic assumption consequently introduces heterogeneity of the adsorption potential, most strongly pronounced near the edges of pore walls. These energetically heterogeneous pores fill with adsorbate more gradually than homogeneous pores. As a result, the calculated adsorption isotherms are smoother and less steep for the finite versus the infinite pore model. We find the agreement between the experiment and the model significantly better for the finite than for the infinite model.