Highly Effective Carbon Fixation via Catalytic Conversion of CO2 by an Acylamide-Containing Metal-Organic Framework

On the way toward a sustainable low-carbon future, in addition to physical capture and permanent underground deposition of anthropogenic emitted CO2, an alternative and very attractive way should be carbon fixation via catalytic chemical conversion of CO2 into value-added chemicals and reusable materials. A metal-organic framework (MOF) incorporating accessible nitrogen-rich groups and unsaturated metal sites was successfully constructed via solvothermal assembly of an acylamide-containing tetracarboxylate ligand and Cu(II) ions. Characterizations including structural analysis, gas adsorption, and Raman spectral detection were carried out to reveal that the MOF presents not only a high porosity with exposed Lewis acid metal sites but also a high CO2-adsorbing capability. Such inherent structural features make the MOF a highly promising candidate as a heterogeneous catalyst for CO2 chemical conversion, which was confirmed by its high efficiency on the CO2 cycloaddition with small-sized epoxides. Due to the size control of the open porous windows, catalytic activity of the MOF shows a sharp difference between small and large epoxides. Remarkably high efficiency and size selectivity on CO2 catalytic conversion enable the MOF to be an advanced heterogeneous catalyst for carbon fixation.