Locking of CO 2 in a Bioinspired Porous-Organic-Polymeric Prison: Impact of Aliphatic Odd–Even Linker Combination

The critical need for better sorbents for CO 2 capture and separation (CCS) is at the forefront of the current research scenario, which is addressed here by synthesizing allomelanin-inspired porous organic polymers (POPs) LPOP - n ( n = 1–5). An investigation into the effect of different linkers on CO 2 adsorption revealed an interesting performance trend, with LPOP-2 showing the highest CO 2 uptake, 3.50 and 3.02 mmol/g at 273 and 298 K, respectively, with impressive CO 2 /N 2 selectivity. Moreover, a dynamic breakthrough experiment revealed a longer breakthrough time for CO 2 than that for N 2, verifying the feasibility of LPOP-2 for its practical application in the CCS process. Density functional theory (DFT) calculations indicated that noncovalent interactions (NCIs), like π-quadrupole interaction and H-bonding, were crucial in dictating the varying CO 2 adsorption behaviors across the LPOP - n series. This work underscores how simple materials originating from biologically active units can produce biocompatible materials for gas adsorption and separation applications.