MELAMINE-BASED POP FOR CO2 CAPTURE AND VALORIZATION

The rapid rise in atmospheric CO₂ due to human activities is a major environmental concern, and carbon capture and storage (CCS) from fossil-fuel power plants is a key mitigation strategy, with porous organic polymers (POPs) emerging as highly promising materials due to their large surface area, tunable pore size and architecture, low density, excellent thermal and chemical stability, and ease of synthesis [1]. Melamine-based porous polymers were synthesized via a one-pot, catalyst-free Schiff base reaction with benzene-1,3,5-tricarboxaldehyde. Slight modifications of the condensation conditions yield porous polymeric network with different porosity and exposure to metalation of N-groups suitable to coordinate. As a matter of fact, post-metalation lead to Re@POPs, using polymer nitrogen atoms as ligands. These materials were tested for gas absorption and electrocatalytic CO₂ reduction. The synthesized Re@POP demonstrated CO₂ absorption properties, albeit reduced compared to the precursor POP [2]. Solid-state 13C CP/MAS NMR, combined with other structural characterization techniques, supports the conclusion that the polymer network is mainly based on aminal linkages rather than imine bonds, in agreement with the reactivity of the amino groups belonging to the electron-rich triazine ring. [2]. Recently, within the same framework aimed at further tailoring the porous structure, we synthesized two distinct melamine-based POPs using different aldehydic precursors, namely 1,4- and 1,3-dicarboxaldehydes. These samples were thoroughly characterized. Solid-state 13C CP/MAS NMR was employed to elucidate the chemical nature of the nitrogen-containing groups within the porous polymeric network too. The resulting POPs were subsequently functionalized with Ag nanoparticles. The findings of this chemical–physical investigation will be presented.