Boosting C2H6/C2H4 separation via the precise electrostatic modulation of synthetic 1-D channel at atomic level

The regulation of gas sorption via simple pore modification is crucial to molecular recognition and chemical separation. Herein, a rational pore surface electrostatic modulation in synthetic one dimensioned (1-D) channel is demonstrated to boost ethane/ethylene (C2H6/C2H4) selectivity for one-step extraction of C2H4 from C2H6/C2H4 mixtures. Through the precise modulation of the surface charge arrangement with negatively charged moieties in the 1-D channel of a metal-organic framework (MOF), enhanced C2H6-host framework and decreased C2H4-host framework electrostatic interactions were obtained, which resulted in an obvious improvement in adsorption selectivity. Furthermore, the breakthrough separation performance rendered the obtained MOF an efficient adsorbent for C2H4 purification from C2H6/C2H4 mixture. The combined detail theoretical studies prove that the gas sorption selectivity is remarkably sensitive to framework electrostatic change even in the case of pore surface modification at the atomic level. These results are of fundamental importance to the design of porous materials for challenging separation tasks.