Efforts for the enhancement of membranes for efficient gas separation are crucial to address challenges in carbon capture and hydrogen economy applications. A novel pore engineering strategy for CMS membranes via ionic liquids (ILs) is presented in this work. Analysis revealed that EmimTf2N functioned as a porogen and a structural modulator during carbonization, creating interconnected pore channels that facilitated efficient gas transport pathways while enabling appropriate d-spacing (3.55 Å) and precise pore formation (2.5-3.5 Å) for size-sieving of H2 (2.89 Å) and CO2 (3.3 Å). By optimizing the EmimTf2N loading and carbonization temperature, the optimal membrane with 3 wt % ILs under 550 °C (PI-3EmimTf2N-550) exhibited a simultaneous enhancement of both high permeability (H2 = 10883.1 Barrer; CO2 = 5697.6 Barrer) and selectivity (H2/N2 = 83.4, H2/CH4 = 113.7, CO2/N2 = 39.8, and CO2/CH4 = 45.5), surpassing the latest Robeson upper bound. Furthermore, the membrane exhibited superior antiplasticization properties and remained stable over 7 days, which was promising for practical H2 and CO2 separation applications.
Song et al. (Thu,) studied this question.