PIL@NENPs composite as a synergetic heterogeneous catalyst to enhance the efficiency of CO2 cycloaddition with epoxides

The conversion CO 2 into highly value-added chemicals requires the development of efficient heterogenous catalysts in the cycloaddition reaction. Herein, the covalent integration strategy of amino-functionalized poly(ionic liquid)s (PIL-NH 2 HBr) with nitrogen-enriched nano-porous polytriazines (NENPs) was used to synthesize a novel hybrid catalyst, labelled as PIL@NENPs. Several characterization techniques were used to confirm the effective synthesis of PIL-NH 2 HBr, NENPs and PIL@NENPs composites. Through the PIL-NH 2 HBr surface integration, the CO 2 adsorption capacity of NENPs was greatly improved in the PIL@NENPs composites. The catalytic activity studies shown that the PIL@NENPs exhibited better catalytic activity than PIL-NH 2 HBr and NENPs in CO 2 cycloaddition reaction due to their synergetic effects. Moreover, the PIL@NENPs composite was found to be very easy to separate, had shown good stability and recyclability, and very effective for a variety of epoxides in the CO 2 cycloaddition reaction. The Density Functional Theory (DFT) calculations further revealed that the epoxides were activated by hydrogen bond donor (HBD) groups and Br anions whereas the CO 2 was activated by N sites. Finally, combining the DFT calculations and activities of different catalysts, a possible reaction mechanism for CO 2 cycloaddition catalyzed by PIL@NENPs was proposed.