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

Abstract

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 C 2 H 2 binding affinity for benchmark trace C 2 H 2 capture from C 2 H 4 . A robust material (ZJU-300a) was elaborately designed to provide multiple-site fluorine binding model, resulting in an ultrastrong C 2 H 2 binding affinity. ZJU-300a exhibits a record-high C 2 H 2 uptake of 3.23 millimoles per gram (at 0.01 bar and 296 kelvin) and one of the highest C 2 H 2 /C 2 H 4 selectivity (1672). The adsorption binding of C 2 H 2 and C 2 H 4 was visualized by gas-loaded ZJU-300a structures. The separation capacity was confirmed by breakthrough experiments for 1/99 C 2 H 2 /C 2 H 4 mixtures, affording the maximal dynamic selectivity (264) and C 2 H 4 productivity of 436.7 millimoles per gram.