fig9

Figure 9. (A) Preparation and characterization of the catalysts; (B) HAADF-STEM images of TWN-Cu_13.35-600-SACs; (C) FE and the product distribution at different potentials. (Reproduced with permission^[105]. Copyright 2023, American Chemical Society); (D) TEM images of Cu-SA/NPC. (E) FE of CO₂RR products on Cu-SA/NPC. [Reproduced with permission^[109]. Copyright 2020, The Author(s)]; (F) Synthetic scheme of Na-PHI, Li-PTI; (G) HRTEM images of Na-PHI; (H) HRTEM images of Li-PTI; (I) FE of CH₄ comparison of Cu-PHI/PTI; (J) Partial current density of CH₄ for the catalysts. (Reproduced with permission^[110]. Copyright 2024, Wiley-VCH GmbH). HAADF-STEM: High-angle annular dark-field scanning transmission electron microscopy; FE: Faraday efficiency; SACs: Single-atom catalysts; TWN: Thin-walled N-doped carbon nanotubes; Cu-SA/NPC: Single-atom Cu on N-doped porous carbon; CO₂RR: Carbon dioxide reduction reaction; TEM: Transmission electron microscope; PHI: Poly (heptazine imide); PTI: Poly (triazine imide); HRTEM: High-resolution transmission electron microscope.