Nickel-based metal–organic framework for efficient capture of CF4 with a high CF4/N2 selectivity

Abstract

Pursuing top-performing materials with excellent structural stability and regeneration to fulfill effective adsorption of tetrafluoromethane (CF4) from the CF4/N2 mixture is of great significance. Herein, a highly stable Ni-MOF, named Ni(ADC)(DABCO)0.5 with anthracene rings-functionalized ultramicroporous chemistry, was prepared to effectively separate the gaseous CF4/N2 blend. Thermodynamic equilibrium adsorption indicates that the Ni(ADC)(DABCO)0.5 owns an excellent CF4 adsorption capacity (0.52 mmol g−1) at 298 K and 0.1 bar, exceeding most of the materials reported until now. Especially, the corresponding selectivity (23.0) at 1.0 bar is higher than that of most existing materials and solves the trade-off issue between CF4/N2 separation selectivity and CF4 uptake. Meanwhile, the separation mechanism underlying the disparity of material affinity toward CF4 and N2 was deciphered via the DFT result. Furthermore, the stronger interaction between the host framework and CF4 molecule is owing to the shorter affinity distance between the pore inner wall and F atom on CF4. Dynamic breakthrough examinations verify this material can utterly separate the CF4/N2 (10/90) blend. In combination with superb framework stability and regeneration, this MOF may be a promising candidate toward the recovery of CF4 from the CF4/N2 mixture.