Heteroatom-doped noble carbon-tailored mixed matrix membranes with ultrapermeability for efficient CO2 separation

Abstract

Membranes with ultrapermeability for CO₂ are desired for future large-scale carbon capture projects, because of their excellent separative productivity and economic efficiency. Herein, we demonstrate that a membrane with ultrapermeability for CO₂ can be constructed by combining N/O para-doped noble carbons, C₂N_xO_1−x, with high-permeability polymer PIM-1. The optimal PIM-1/C₂N_xO_1−x membranes exhibit superior CO₂ permeability (22110 Barrer) with a CO₂/N₂ selectivity of 15.5, and an unprecedented CO₂ permeability of 37272 Barrer can be obtained after a PEG activation treatment, far surpassing the 2008 upper bound. Both broad experiments and molecular dynamics simulations reveal that the numerous ordered polar channels of C₂N_xO_1−x and their excellent compatibility with PIM-1 are responsible for the superior CO₂ separation performance of the membrane. Although this is the first study on C₂N-type gas separation membranes, the outstanding results indicate that noble carbon building blocks may pave a new avenue to advance high-performance CO₂ separation membranes.