Abstract
Membrane technology lies at the heart of many industrial gas separation processes and applications. Molecular sieving membranes that break the Robeson limit are desirable for energy-efficient gas separation. Herein, we report a facile strategy of directly integrating ionic liquids (ILs) into porous membranes. Particularly, the ILs form an ultra-thin layer on the carbon molecular sieve (CMS) membranes rather than penetrating into the pores, acting as a smart gate for gas entry to boost the selectivity. The hybrid membrane exhibits CO2 permeability >600 barrer and enhanced CO2/N2 selectivity >50, which surpasses the Robeson limit and shows potential in CO2/N2 separation process. Molecular dynamics simulations confirm the gating effect of the IL layer of molecular thickness. This work demonstrates a universal strategy to improve CMS membrane performance by creating an IL-membrane interface and tuning the ion-pore interaction.
