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