Design of a highly-stable cobalt (II) porous framework based on aromatic stacking strategy for efficient SF6 capture and SF6/N2 mixture separation

Effective capture and separation of the greenhouse gas SF6 from N2 is extremely important to attenuate the greenhouse effect and bring economic benefits to the semiconductor industry. Herein, a highly stable “pillar-layer” MOF (YTU-30) with multiple π-π stacking aromatic rings as pillar in the pores was prepared by mixed ligand strategy. Static equilibrium isothermal adsorption results display that YTU-30 possesses a high SF6 uptake capacity (68.6 cm3 cm−3), while nearly negligible N2 adsorption (3.3 cm3 cm−3) at 298 K and 1 bar. The substance ratio of SF6-to-N2 uptake reached 20.8. Dynamic breakthrough experiments also demonstrate that YTU-30 can achieve the effective separation of SF6/N2 (10/90) mixture. Cycling experiments of static and dynamic were unchanged with a very simple process, which further confirmed the feasibility and directly capture SF6 and separate the SF6/N2 mixture for YTU-30. The dense aryl rings with π-π stacking in the pores not only increases the stability of MOF, but also contributes to its high SF6 adsorption. These results provide a new strategy to achieve the construction of a stable MOF for the separation SF6/N2 gas mixture.