Repairing Lattice Defects by an Orienting Strategy in a Porous Crystal: Boosting Inverse C₂H₆/C₂H₄ Separation

Abstract

Defects are a common occurrence in various materials, making their repair a topic of widespread attention. However, the repair of atomic‐scale lattice defects in porous crystals presents a substantial challenge. Herein, the repair of a linker‐defective framework (NTU‐70D) is presented through an orienting strategy to obtain a perfect framework (NTU‐70P). Caused by steric hindrance from adjacent carboxylates of isonicotinic acid (INA), the lattice linker defect in NTU‐70D is repaired by formic acid‐assistant (pushed to the opposite direction by steric hindrance) installation of additional INAs in a defined direction, an unprecedented example in PCP chemistry. The resulting NTU‐70P exhibits regular and smooth nano‐channels that are adorned with more O_INA sites, leading to a significant increase in C₂H₆ uptake (51.0 to 90.2 cm³ g⁻¹) and C₂H₆/C₂H₄ selectivity (1.6 to 2.5), as evidenced by modeling calculations and in situ IR analysis. Furthermore, it demonstrates a notable ability to produce poly‐grade C₂H₄ (with a record value of 46.4 mL g⁻¹) from C₂H₆‐containing mixtures. This work presents the first example of repaired porous crystals for boosted inverse C₂H₆/C₂H₄ separation, and the insights gained into the lattice repair offer avenues for the development of rich defective systems in practical applications.