Fabrication of a Nitrogen-Rich Porous Polymer Network with Dense Polytriazine and Polytetrazine for CO₂ Capture

Porous polymer networks are considered potential candidates for CO₂ capture, owing to their well-developed porosity and high stability. However, their further application is limited by the relatively low selectivity and unsatisfactory adsorption capacity. In this study, we fabricated a nitrogen-rich porous polymer network, denoted as NRPPN-1, with dense polytriazine and polytetrazine by polymerization of two monomers of melamine and 3,6-dichloro-1,2,4,5-tetrazine. The resulting NRPPN-1 exhibits an abundance of micropores and a high surface area of 668 m²·g^-1. Experimental results demonstrate that NRPPN-1 has excellent CO₂ adsorption capacity (181.2 mg·g^-1) and adsorption selectivity (306.4) at 273 K and 100 kPa for CO₂/N₂ mixtures, which are corroborated by adsorption potential and breakthrough curve analysis. Moreover, computational simulations reveal that the abundant nitrogen-rich active sites in NRPPN-1 induce strong C···N interactions, which are responsible for the promoted selective capture of CO₂ from CO₂/N₂ mixtures. The novel nitrogen-rich porous polymer network may serve as a promising candidate for the capture of CO₂ from flue gas.