Cost-Effective, Hydrogen-Rich, and Ultramicroporous Metal-Organic Framework for Efficient Separation of SF6 from N2.

It is essential for the industry to create an adsorbent that combines a high capacity with selectivity to achieve the effective separation of SF₆ from gas mixtures. In this study, we prepared a cost-effective nickel-based metal-organic framework (MOF), Ni(BTC)(BPY), which features hydrogen-rich ultramicroporous channels specifically designed for separating SF₆/N₂ gas mixtures. The findings from the adsorption experiments demonstrated that Ni(BTC)(BPY) achieved a remarkable SF₆ adsorption capacity of 5.08 mmol g^-1 and an ideal adsorbed solution theory SF₆/N₂ selectivity of 382. This effectively resolves the trade-off encountered in the development of adsorbents between capacity and selectivity. Theoretical calculations indicated the optimal adsorption sites for SF₆ within the pore channels. The strong interactions between the F atoms in SF₆ and the numerous H atoms in the channels account for the superior SF₆ adsorption performance of this material. Breakthrough experiments provided additional evidence that the MOF can completely separate SF₆/N₂ mixtures, positioning it as an excellent candidate for recovering SF₆ from these gas mixtures.