Construction of multifunctional histidine-based hypercrosslinked hierarchical porous ionic polymers for efficient CO2 capture and conversion

Several novel multifunctional histidine-based hypercrosslinked ionic polymers (HIPs) were constructed via a one-pot copolymerization strategy. The resultant HIPs were characterized by various technologies and investigated for the CO2 adsorption and conversion. Plentiful hydrogen bond donors, nucleophilic ionic sites, and Lewis bases were successfully integrated into the HIPs skeletons. As-prepared histidine-based HIPs possess excellent hierarchical pore structure. The optimal HIP-Br-His exhibits a high CO2 capture capacity of 2.90 mmol/g at 273 K and 1 bar, much higher than that of corresponding hypercrosslinked polymer HCP-Br without histidine units. Meanwhile, the HIP-Br-His achieves an excellent catalytic activity of 95 % product yield with 99 % product selectivity in CO2 cycloaddition to propylene oxide under metal-, cocatalyst- and solvent-free and mild conditions (70 °C and 1.0 MPa). Particularly, HIP-Br-His can efficiently capture and convert dilute CO2 into cyclic carbonates with a satisfactory catalytic performance. The excellent catalytic activity associating with the confirmed good stability, recyclability, and substrate compatibility make the developed histidine-based HIPs a promising heterogeneous catalyst for efficient CO2 capture and conversion.