Expandable porous organic frameworks with built-in amino and hydroxyl functions for CO2 and CH4 capture

Abstract

The synthesis of porous organic 3D frameworks, wherein amine, hydroxyl and Li-alkoxide functions were built directly on the monomer-unit carbon core, realizes improved interactions with target gases. CO₂ was retained by the amine group with a remarkable energy of 54 kJ mol⁻¹, while 2D MAS NMR provided rare evidence of amine-to-gas short-distance interactions. Frameworks containing hydroxyl and Li-alkoxide functions show optimal interaction energies with CH₄ of up to 25 kJ mol⁻¹. The light network of 3-branch building units ensures the expandability of the nano-sponges.