Interpreting the Ultramicroporous Structure of Carbon Molecular Sieves

Abstract

We report the textural and neutron total scattering studies of carbon molecular sieves (CMSs) to gain holistic insight into their ultramicroporous structure. CMS materials derived from the pyrolysis of PIM-1 (PIM = polymer of intrinsic microporosity; PIM-1-CMS ) under inert atmosphere and H 2 atmosphere ( 4% H 2 -PIM-1-CMS ) were studied. Neutron total scattering studies of these materials reveal these CMS materials to be mainly graphene-like ribbons with short-range atomic ordering. Small-angle X-ray scattering and low angle diffraction peaks corroborate the presence of well-defined porosity observed in cryogenic neon adsorption studies suggesting, expectedly, that these materials are non-graphitizing carbon structures. The findings herein provide microscopic evidence of the non-graphitizing and ribbon-like structure of these CMS materials and suggest a possible hypothetical microporous structure.

Keywords: Carbon molecular sieve, amorphous microstructure, neutron total scattering, small angle scattering, neon physisorption