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

Abstract

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.