Tuning Gate-Opening of a Flexible Metal-Organic Framework for Ternary Gas Sieving Separation.

In comparison with the fast development of binary mixture separations, ternary mixture separations are significantly more difficult and have rarely been realized by a single material. Herein, a new strategy of tuning the gate-opening pressure of flexible MOFs is developed to tackle such a challenge. As demonstrated by a flexible framework NTU-65, the gate-opening pressure of ethylene (C H ), acetylene (C H ), and carbon dioxide (CO ) can be regulated by temperature. Therefore, efficient sieving separation of this ternary mixture was realized. Under optimized temperature, NTU-65 adsorbed a large amount of C H and CO through gate-opening and only negligible amount of C H . Breakthrough experiments demonstrated that this material can simultaneously capture C H and CO , yielding polymer-grade (>99.99 %) C H from single breakthrough separation.