Development of a simple NLDFT model for the analysis of adsorption isotherms on zeolite templated carbon (ZTC)

Abstract

In this study, we present a systematic search for a simple geometrical pore model relating the N2 adsorption data on zeolite templated carbon (ZTC) to its pore size distribution (PSD). Based on the known genesis of the templated carbon and the literature studies suggesting its curved pore structure, we explore possible applicability of simple geometrical pore models for the PSD analysis of the ZTC N2 adsorption isotherm. The isotherm analysis is performed using the models based on the two-dimensional version of the non-local density functional theory (2D-NLDFT). We consider finite and continuous curved cylindrical pores. In agreement with XRD results showing no stacked graphene sheets in the calculations, we assume pore walls to be constructed by single-layer graphenes. In the PSD analysis of the ZTC nitrogen adsorption isotherm using NLDFT models assuming different shapes and length of finite pores as well as continuous curved pores of various curvatures. Based on these analyses, we selected an optimal NLDFT adsorption model that is consistent with the ZTC structure described by the atomistic structural model. The periodicity of this optimal model practically coincides with the periodicity of the ZTC lattice that was uncovered by the TEM image reported in the earlier study.