Scalable room temperature incorporation of CO2-selective ångström-scale pores in graphene for carbon capture

Abstract

Atom-thin porous graphene membranes offer unprecedented carbon capture performance thanks to Å-scale pores that combine ultrahigh permeance with attractive selectivity. However, incorporating a high pore density has until now required elevated-temperature ozone oxidation, while oxidation at room temperature was found to be sluggish, limiting scalability. Herein, we uncover that graphene oxidation by ozone is constrained by mass transfer of ozone and concentration polarization from the accumulation of reaction byproduct at the surface. We overcome this bottleneck using micro-channeled flow reactor that enhances mass transfer, accelerating the oxidation rate, leading to a tenfold higher pore density at room temperature. Centimeter-scale porous graphene with a high density of CO2-selective pores is achieved, resulting in CO2/N2 selectivity up to 21 and CO2 permeance up to 4050 gas permeation units. A brief subsequent room-temperature pore-expansion step further boosts performance. Our fully ambient, scalable protocol eliminates high-temperature equipment and provides a practical route to industrial production of porous graphene membranes for carbon capture.