Achieving selective CO2 capture and separation in crosslinked porous porphyrin-based polyimide skeletons

Abstract

The precise control of porous structure has always been a key factor for porous materials. We tuned the porous structures by enhancing alkynyl-groups contents and introducing metal into porphyrin ring. We used simple polymerization and alkynyl crosslinking reactions to construct crosslinked porous porphyrin-based polyimides (CR-PPBPIs) from 2,5-bis(3,4-dicarboxyphenoxy)-4’-phenylethynyl-biphenyl dianhydride (PEPHQDA) and 5,10,15,20-tetra[4-[(3-aminophenyl)ethynyl]phenyl] porphyrin (TAPEPP). CR-PPBPIs revealed BET surface areas (212, 578 and 593 m2 g−1), dominated pore width (1 and 1.9 nm) and abundant CO2-philic substances. Thus, considerable CO2 uptakes (1.92, 2.43 and 2.52 mmol g−1), CO2-adsorption isosteric enthalpies (31.9, 26.0 and 27.9 kJ mol−1) and superior CO2/N2 selectivities (45.77, 38.72 and 46.26) were achieved. This work sheds some light on the precise regulation of porosity parameters in the crosslinked metalloporphyrin-based polyimides for carbon dioxide adsorption and separation.