Construction of bifunctional triazine-based imidazolium porous ionomer polymers by a post-crosslinking tactic for efficient CO2 capture and conversion

Porous ionomer polymers (PIPs), as a class of materials with special functions, have been extensively studied due to their easy preparation and designability. In this work, a series of novel triazine imidazolium functionalized PIPs are successfully constructed by a post-crosslinking tactics for CO2 capture and conversion. Both structure and properties of PIPs are adjusted neatly by changing ionic salt monomers (ISM-n) and external cross-linkers p- xylylene dichloride (DCX), alpha,alpha'-dibromo-p-xylene (DBX), and 4,4 '-bis(chloromethyl)-1,1 '-biphenyl (BP), as well as the cross-linked ratios. It is found that the CO2 adsorption capacity of as-prepared PIPs constructed by post-crosslinking strategy is significantly increased from 9.3 to 103.2 mg.g(-1 )at 273 K and 1.0 bar than corresponding ionic salt monomer (an improvement of about 10 times). Kinetic and thermodynamic studies for CO2 adsorption processes indicate that the adsorption of CO2 by PIPs is a spontaneous physical adsorption process. Particularly, these triazine-based imidazolium PIPs can also be used as recyclable catalysts for CO2 conversion into cyclic carbonates with up to 99 % yields and the unprecedented turnover number (TON) of 4025, it is much higher than those ionic polymer catalysts reported in previous literature. Combined CO(2 )reaction kinetics, reaction activation energies catalyzed by different catalysts, and in situ FTIR experimental results of CO2 adsorption and conversion, a synergistic catalytic mechanism based on triazine group and imidazolium is proposed. Our study provides new insights into the design of functionalized PIPs materials with great potential for applications in CO2 separation and conversion.

Automated summary

In this study, a series of porous ionomer polymers (PIPs) with special functions were successfully constructed for CO2 capture and conversion. By adjusting the structure and properties, as well as the cross-linked ratios, the CO2 adsorption capacity and catalytic performance of PIPs were greatly improved. The results show that these functionalized PIPs have great potential for applications in CO2 separation and conversion.