Role of aromatic ring spacer in homo‐coupled conjugated microporous polymers in selective CO 2 separation

To obtain high purity of natural and flue gases, the development of adsorbent with appropriate structure is of great importance. As a result, there is an urgent need to investigate the role of aromatic ring spacer in adsorbent in high CO 2 capture. For this, conjugated microporous polymers (CMPs) were fabricated through homo‐coupling reaction of 1,3,5‐tribromobenzene (TBB) and 1,3,5‐triethynylbenzene (TEB). It was observed that, CMP‐A (without spacer) demonstrates high CO 2 uptake over CMP‐B (with spacer). CMP‐A demonstrates CO 2 uptake of 212.1 mg g −1 which is obviously higher than benchmark adsorbents under the analogous conditions. In addition, the obtained CO 2 uptake is also higher than metal–organic framework (MOF) and energy‐intensive carbon‐based adsorbents. CMP‐A revealed high CO 2 /N 2 selectivity (78.5) over CMP‐B (56.1). It was noticed that CMP‐A demonstrates excellent CO 2 /CH 4 and CO 2 /N 2 selectivity over CMP‐B at 273 K. This is mainly due to appropriate structure in CMP‐A (without spacer). The obtained CO 2 /N 2 selectivity (78.5) is higher than recently reported adsorbents under the similar experimental conditions.