Hierarchical Porous and Zinc-Ion-Crosslinked PIM-1 Nanocomposite as a CO2 Cycloaddition Catalyst with High Efficiency.

CO2 cycloaddition to epoxides is an effective and economical utilization method to alleviate the current excessive CO2 emission situation. The development of catalysts with both high catalytic efficiency and high recyclability is necessary but challenging. In this context, a heterogeneous catalyst was synthesized based on a zinc-ion-crosslinked polymer with intrinsic microporosity (PIM-1). The high microporosity of PIM-1 promoted a high Zn2+ loading rate. Additionally, the relatively stable ionic bond formed between Zn2+ and the PIM-1 framework through electrostatic interaction ensured high loading stability. In the process of CO2 cycloaddition with propylene epoxide, an optimized conversion of 90 % with a turnover frequency as high as 9533 h-1 could be achieved within 0.5 h at 100 °C and 2 MPa. After 15 cycles, the catalytic efficiency did not demonstrate a significant decline, and the catalyst was able to recover most of its activity after Zn2+ reloading. This work thereby provides a strategically designed CO2 conversion catalyst based on an ionic crosslinked polymer with intrinsic microporosity.