Microwave-synthesized heteroaromatic porous organic polymers for CO2 capture and hydrogen storage

Abstract

In this paper, three porous organic polymers (POPs) were synthesized by microwave-assisted Friedel-Crafts polymerization reaction of 1,3,5-tris(2-thienyl)benzene (TTB) with furan (HAF), thiophene (HAT), and pyrrole (HAP) in the presence of dimethoxymethane using anhydrous iron (III) chloride as a catalyst. The polymers displayed inherent porosity, with BET surface areas ranging from 528 to 634 m2/g. These polymers exhibited high CO2 adsorption capacity, with values of 2.61, 2.17, and 2.37 mmol/g at 273 K and 1 atm, as well as strong affinity, with Qst values of 43–48 kJ/mol. The polymers showed hydrogen storage of 3.3–5.3 mmol/g (0.66–1.06 wt%) at 77 K, and 1 atm. The polymers showed Initial slope selectivity for CO2/N2: 34–61 at 273 K and 1 atm, and 23–57 at 298 K and 1 atm. Whereas, the polymers showed initial slope selectivity for CO2/CH4: 5–9 at 273 K and 4–7 at 298 K and 1 atm. Besides, the HAP at 273 K and HAF at 298 K showed highest IAST selectivity values of 231.18 and 257.49, respectively. Grand Canonical Monte Carlo (GCMC) simulations revealed that the polymers exhibit matching electronic properties with CO2 molecules and achieve excellent selectivity in accordance with the hard-soft acid-base (HSAB) theory. These findings demonstrate the potential of these polymers for CO2 capture and clean energy applications.