fig4

Figure 4. (A) LSV curves from -0.5 to -1.0 V in 0.5 M KHCO₃ under CO₂ atmosphere (line) and Ar atmosphere (dot); (B) Tafel slopes; (C) CO faradaic efficiency; (D) The partial CO current density; (E) The ECSA slopes; (F) The CO current density by the normalized ECSA for Co-COF (black) and TMA-COF (red). LSV: Linear sweep voltammetry; ECSA: electrochemically active surface area; COF: covalent organic framework; TMA-COF: (3-carboxypropyl)trimethylammonium covalent organic framework.