Defluorinated Porous Carbon Nanomaterials for CO₂ Capture

This paper described a facile preparation of a fluorinated covalent triazine framework (2F-CTF) via an AlCl3-catalyzed Friedel–Crafts reaction and the employment of 2F-CTF as the precursor to prepare defluorinated porous carbon nanomaterials (df-CTF-KT) with the aid of KOH. The C–F bonds can generate reactive fluorinated species during carbonization and etch the precursor’s backbone to afford improved porosity. Especially, df-CTF-K700 exhibited a higher surface area and microporosity when compared with the precursor 2F-CTF (1914 vs 1122 m2 g–1 and 0.633 vs 0.282 cm3 g–1) and thus afforded increased CO2 uptake under 1 bar (391 vs 215 mg g–1 at 273 K and 218 vs 101 mg g–1 at 298 K). A non-fluorinated CTF and its carbonization product were synthesized to understand the important role of fluorine in CTFs and porous carbon nanomaterials. Both 2F-CTF and df-CTF-K700 showed higher CO2 uptake capacity than the non-fluorinated CTF and derived porous carbons, respectively. Importantly, the CO2 uptake capacity of df-CTF-K700 is much better than most of the reported porous carbons and other porous adsorbents, and the Qst value at zero coverage is 27.3 kJ mol–1, affording the facile desorption process.