Tuning the Surface Polarity of Microporous Organic Polymers for CO 2 Capture

CO 2 capture is very important to reduce the CO 2 concentration in atmosphere. Herein, we report the preparation of microporous polymers with tunable surface polarity for CO 2 capture. Porous polymers functionalized with ‐NH 2 , ‐SO 3 H, and ‐SO 3 Li have been successfully prepared by using a post‐synthesis modification of microporous polymers (P‐PhPh 3 prepared with 1,3,5‐triphenylbenzene as the monomer and AlCl 3 as the catalyst) by chemical transformations, such as nitration–reduction, sulfonation, and cationic exchange. The CO 2 adsorption selectivity (CO 2 /N 2 and CO 2 /H 2 ) and isosteric heats of the microporous polymers increase markedly after modification, P‐PhPh 3 ‐NH 2 and P‐PhPh 3 ‐SO 3 Li afford higher CO 2 uptake capacity than P‐PhPh 3 at pressures of less than 0.15 bar due to the enhanced interaction between CO 2 and the ‐NH 2 and ‐SO 3 Li functional groups. Moreover, functionalized porous polymers could be stably used for CO 2 capture. Surface modification is an efficient approach to tune the CO 2 capture properties of porous polymers.