Pyrazine‐interior‐embodied <scp>MOF</scp>‐74 for selective <scp>CO<sub>2</sub></scp> adsorption
Meng Zhao, Yujie Ban, Ze Chang, Yingwu Zhou, Kun Yang, Yuecheng Wang, Na Cao, Weishen Yang
Abstract
Abstract A series of pyrazine‐interior‐embodied metal–organic framework‐74 composites (py‐MOF‐74) were successfully synthesized by a post‐synthetic vapor modification method. Here, pyrazine molecules occupy the cavity to block the wide pores of MOF‐74, which accentuates the difference in adsorption of a pair of gases on MOFs and consequently reinforces the adsorption selectivity. Different from the “physical confinement” of occupants, the pyrazine molecule with dual “para‐nitrogen” atoms donates one N atom to bond with the open metal ion of MOF‐74 for stability and the other N atom for potential CO 2 trapping. Typically, py‐MOF‐74c with the highest pyrazine insertion ratio displays selectivity greatly superior to that of MOF‐74 in equimolar CO 2 /CH 4 (598 vs. 35) and in simulated CO 2 /N 2 flue gas (471 vs. 49). Py‐MOF‐74 entities are long‐lived adsorbents, and their CO 2 capacity can be maintained even after storage for 1 year in air. Py‐MOF‐74 also showed a sharp molecular sieve property in fixed‐bed cycle adsorption tests, which implies its great potential in real applications.