Synthesis of [3 + 3] β-ketoenamine-tethered covalent organic frameworks (COFs) for high-performance supercapacitance and CO2 storage

We report three new β-ketoenamine-linked covalent organic frameworks (COFs) prepared through Schiff-base [3 + 3] polycondensations of 1,3,5-triformylphloroglucinol (TFP-3OHCHO) with three tris(aminophenyl)-presenting derivatives—featuring amino, carbazole, and pyridine units, respectively under solvothermal conditions. The resultant TFP-COFs possessed high BET specific surface area up to 686 m2 g–1 and excellent crystallinity, which showed excellent electrochemical specific capacitances (up to 291.1 F g–1) and CO2 uptake efficiency up to 200 mg g–1 at 273 K. We propose the enhanced performance in supercapacitor and gas storage is owing to the conjugated enamine structures with redox-active triphenyl amino, carbazole, and pyridine moieties. In addition, we further investigate the formation mechanism of the spherical TFP-TPA COF by studying the morphological changes over time. The presence of more highly planar monomer units in the hexagonal structures of the resultant COFs led to stronger quadrupolar interaction with the included CO2 molecules.