Robust tri(4-ethynylphenyl)amine-based porous aromatic frameworks for carbon dioxide capture

Abstract

We report here the synthesis and carbon dioxide capture of a series of porous aromatic framework (PAF) materials assembled using tri(4-ethynylphenyl)amine and various aryl halides via Sonogashira–Hagihara coupling reactions. These PAF materials show moderate surface areas ranging from 370 m² g⁻¹ to 953 m² g⁻¹. The functional groups, such as –COOH, –NH₂ and –OH, are incorporated into the backbone of the PAF materials. The isosteric heats of CO₂ and CO₂/N₂ selectivities for these PAFs are calculated based on the CO₂ and N₂ adsorption isotherms measured at 273 and 298 K. It is found that the –NH₂ functionalized network shows the highest isosteric heat of CO₂ and CO₂/N₂ selectivity. In addition, the –COOH functionalized network displays the highest CO₂ uptake in terms of per unit areas (4.37 μmol m⁻², 273 K). The results indicate the incorporation of functional groups is effective for synthesizing CO₂-philic PAF networks with enhanced interaction with CO₂ molecules.