fig2

Figure 2. (A) The nitrogen-sorption isotherms at 77 K of Co-COF (black) and TMA-COF (red); The pore distribution curves of (B) Co-COF and (C) TMA-COF; (D) The CO₂ adsorption curves at 298 K for Co-COF (black) and TMA-COF (red). COF: Covalent organic framework; TMA-COF: (3-carboxypropyl)trimethylammonium covalent organic framework.