Polyacrylonitrile‐Derived Sponge‐Like Micro/Macroporous Carbon for Selective CO₂ Separation

Abstract

CO₂ capture under a dynamical flow situation requires adsorbents possessing balanced proportion of macropores as diffusion path and micropores as adsorption reservoir. However, the construction of interconnected micro-/macropores structure coupled with abundant nitrogen species into one carbon skeleton remains a challenge. Here, we report a new approach to prepare sponge-like carbon with a well-developed micro-/macroporous structure and enriched nitrogen species through aqueous phase polymerization of acrylonitrile in the presence of graphene oxide. The tension stress caused by the uniform thermal shrinkage of polyacrylonitrile during the pyrolysis together with the favorable flexibility of graphene oxide sheets are responsible for the formation of the sponge-like morphology. The synergistic effect of micro-/macroporous framework and rich CO₂ -philic site enables such carbon to decrease resistance to mass transfer and show high CO₂ dynamic selectivity over N₂ (454) and CH₄ (11), as well as good CO₂ capacity at 298 K under low CO₂ partial pressure (0.17 bar, a typical CO₂ partial pressure in flue gas). The above attributes make this porous carbon a promising candidate for CO₂ capture from flue gas, methane sources and other relevant applications.