4 | Conclusions
In summary, pyrazine-interior-embodied MOF-74 composites were prepared through a post vapor modification process. Owing to the blocking effect of pyrazine molecules, the composites can significantly widen the adsorption gaps between CO2 and its counterparts (CH4 and N2), resulting in lower saturation uptake for gases albeit with much higher selectivity. We also underline the stability of pyrazine-interior-embodied MOF-74. Pyrazine molecules can hardly escape from the composites at its boiling point, and the composites display higher thermal stability than the parent framework MOF-74, which is attributed to the chemical insertion of pyrazine to the open metal ions of MOF-74. The pyrazine-interior-embodied MOF-74 composites that display significant CO2 selectivity and moderate adsorption enthalpies would be good candidates in dynamic adsorption-based separation and membrane separation.