Programmed fluorine binding engineering in anion-pillared metal-organic framework for record trace acetylene capture...

Porous physisorbents are attractive candidates for selective capture of trace gas or volatile compounds due to their low energy footprints. However, many physisorbents suffer from insufficient sorbate-sorbent interactions, resulting in low uptake or inadequate selectivity when gases are present at trace levels. Here, we report a strategy of programmed fluorine binding engineering in anion-pillared metal-organic frameworks to maximize C₂H₂ binding affinity for benchmark trace C₂H₂ capture from C₂H₄. A robust material (ZJU-300a) was elaborately designed to provide multiple-site fluorine binding model, resulting in an ultrastrong C₂H₂ binding affinity. ZJU-300a exhibits a record-high C₂H₂ uptake of 3.23 millimoles per gram (at 0.01 bar and 296 kelvin) and one of the highest C₂H₂/C₂H₄ selectivity (1672). The adsorption binding of C₂H₂ and C₂H₄ was visualized by gas-loaded ZJU-300a structures. The separation capacity was confirmed by breakthrough experiments for 1/99 C₂H₂/C₂H₄ mixtures, affording the maximal dynamic selectivity (264) and C₂H₄ productivity of 436.7 millimoles per gram.