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

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 N-2 (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.