Coupling modes of (A) CO₂ and HCOOH absorbed on COF-367-Co^II and COF-367-Co^III. Reproduced with permission from ref. [134]. Copyright©2020, American Chemical Society. Limiting potentials of (B) early transition metal and (C) late transition metal. Reproduced with permission from ref. [139]. Copyright©2019, American Chemical Society. (D) Absorption volcano graph of Fe-N₄-C, Fe-N₃/P-C, Fe-N₄/P-C, and Fe-N₄-Vac-P-C for the electroreduction of CO₂ to CO. Reproduced with permission from ref. [140]. Copyright©2022, American Chemical Society. Theoretical and corresponding experimental (E) onset potentials for ORR and (F) overpotentials for HER vs. the descriptor φ. Reproduced with permission from ref. [141]. Copyright©2018, Springer Nature. (G) Calculated ΔG(*H) and ΔG(*N₂) on SACs. SACs in *N₂ dominant region (under the dashed line, ΔG(*H) > ΔG(*N₂)) correspond to N₂ adsorption being more favorable than *H formation at 0 V (vs. RHE). Reproduced with permission from ref. [142]. Copyright©2018, American Chemical Society. (H) Bare carbon substrate and five different Fe-N-C coordination structures. Reproduced with permission from ref. [143]. Copyright©2020, Royal Society of Chemistry. (I) Electrochemical potential window of Ni/NC and the corresponding model of Ni₂₀/NC and (SA-Ni)₂/NC). Reproduced with permission from ref. [144]. Copyright©2020, American Chemical Society.