Insensitivity in the pore size distribution of ultramicroporous carbon materials by CO2 adsorption

Abstract

Accurate quantification of ultramicropores is critical to optimizing and understanding the performance of carbon materials in many applications. The pore size distributions (PSD) were calculated from the CO2 adsorption isotherms by Non-local Density Functional Theory (NLDFT) and Grand Canonical Monte Carlo simulations (GCMC). The PSDs obtained using a pseudo-spherical potential for CO2 interaction have the same qualitative behavior, reporting several peaks in the ultramicroporous region. These results contradict the hypothesis that highly disordered microporous carbon materials have a widely distributed PSD without sharp spikes. In this work, we investigate the insensitivity in the characterization of different microporous materials and the origin of the artificial gaps that arise in models with pseudo-spherical potential (NLDFT and GCMC). Furthermore, we study the characterization of these materials using Monte Carlo simulations, which incorporate the multi-site model potential achieving improved PSDs.