fig9

Figure 9. (A) Schematic presentation of different COF-based composites; (B) Free energy diagrams, DOS and d band centers of Co-SA, Co-NP and Co-SA/Co-NP^[136]; (C) Illustration and morphology characterization of ZIF-L@PDA-FePhen and Fe-N₄@NC-PCSs^[144]; (D) Fabrication of Mo SACs with O/N/S co-coordination. Structural characterization of MoS₄^2--doped polydopamine hollow spheres; (E) Favorable reaction pathway of single Mo atom supported on the Mo-O₂NS-C structure^[145]; (F) Illustration of CB[6]-derived M-N-C SACs; (G) Structural characterization of CB[6]-derived M-N-C catalysts^[146]; (H) Morphology characterization, and (I) electrochemical performance of M-N©HCS catalysts^[135]. SACs: Single atom catalysts; N: nitrogen; S: sulfur.