De-Linker-Enabled Exceptional Volumetric Acetylene Storage Capacity and Benchmark C2 H2 /C2 H4 and C2 H2 /CO2 Separations in Metal-Organic Frameworks.

ABSTRACT

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 C2 H2 uptake capacity under low and ambient pressures (175.3 cm3 cm-3 @ 0.1 bar, 222.9 cm3 cm-3 @ 1 bar, 298 K), as well as extraordinary selectivity (2405.7 for C2 H2 /C2 H4 , 22.7 for C2 H2 /CO2 ). Remarkably, SNNU-98-Mn can efficiently separate C2 H2 from C2 H2 /CO2 and C2 H2 /C2 H4 mixtures with a benchmark C2 H2 /C2 H4 (1/99) breakthrough time of 2325 min g-1 , and produce 99.9999 % C2 H4 with a productivity up to 64.6 mmol g-1 , surpassing values of reported MOF adsorbents.