De‐Linker‐Enabled Exceptional Volumetric Acetylene Storage Capacity and Benchmark C₂H₂/C₂H₄and C₂H₂/CO₂Separations in Metal–Organic Frameworks

An ideal adsorbent for separation requires optimizing both storage capacity and selectivity, but maximizing both or achieving a desired balance remain challenging. Herein, a de‐linker strategy is proposed to address this issue for metal–organic frameworks (MOFs). Broadly speaking, the de‐linker idea targets a class of materials that may be viewed as being intermediate between zeolites and MOFs. Its feasibility is shown here by a series of ultra‐microporous MOFs (SNNU‐98‐M, M=Mn, Co, Ni, Zn). SNNU‐98 exhibit high volumetric C 2 H 2 uptake capacity under low and ambient pressures (175.3 cm 3 cm −3 @ 0.1 bar, 222.9 cm 3 cm −3 @ 1 bar, 298 K), as well as extraordinary selectivity (2405.7 for C 2 H 2 /C 2 H 4 , 22.7 for C 2 H 2 /CO 2 ). Remarkably, SNNU‐98‐Mn can efficiently separate C 2 H 2 from C 2 H 2 /CO 2 and C 2 H 2 /C 2 H 4 mixtures with a benchmark C 2 H 2 /C 2 H 4 (1/99) breakthrough time of 2325 min g −1 , and produce 99.9999 % C 2 H 4 with a productivity up to 64.6 mmol g −1 , surpassing values of reported MOF adsorbents.