Stepped enhancement of CO2 adsorption and separation in IL‐ZIF‐IL composites with shell‐interlayer‐core structure

Abstract Development of materials with excellent separation performance remains an ongoing challenge in separation science and technology. Herein, a novel strategy was proposed to gradually enhance gas separation performance in micro/nano‐materials, by constructing a shell‐interlayer‐core structure using ionic liquid (triethylenetetramine lactate, [TETA]L) and zeolitic imidazolate framework (ZIF‐8). Such structure includes outer [TETA]L shell, interlayer of ZIF‐8, and inner [TETA]L core, endowing the composite with more evident molecular sieving separation for CO 2 mixtures than the reported materials. A high CO 2 adsorption amount (1.53 mmol/g at 298 K and 1.0 bar) is maintained, while the uptakes for CH 4 and N 2 are very low. Corresponding ideal adsorbed solution theory selectivities are 260–1,990 and 1,688–5,572 for CO 2 /CH 4 and CO 2 /N 2 mixtures at the range of tested pressures. In addition, the separation performance can be controlled by varying the shell‐interlayer‐core structure with IL inside, outside or on both sides of ZIF‐8 and the thickness of outer shell.