Synergistic Catalysis in Defect-Engineered Zn-MOF-74-Based Porous Liquids for Enhanced CO2 Cycloaddition Under Mild Conditions.

Porous liquids (PLs), which combine permanent porosity with fluidity, represent an emerging class of materials with broad application prospects. The incorporation of catalytic sites into both the porous framework and the liquid medium further enables their use in catalysis. Here, we report a type III porous liquid (PL-Zn-MOF-74-DF) fabricated from a functional imidazolium-based ionic liquid (IL1) and defective Zn-MOF-74-DF, which exhibits enhanced CO2 capture capacity and superior performance in the cycloaddition of CO2 to epoxides compared to IL1 alone. Under mild conditions (50°C, 1 bar), the designed porous liquid boosts the conversion of styrene oxide (SO) by up to 22.6% and that of propylene oxide (PO) by 29.9%. Density Functional Theory (DFT) calculations reveal that the remarkable catalytic enhancement stems from the synergistic interplay between IL1 and the defective metal sites in Zn-MOF-74-DF, which facilitates CO2 activation and stabilizes key reaction intermediates. This work provides both experimental and theoretical insights into the catalytic mechanism of porous liquids, paving the way for their rational design in sustainable catalysis.