fig1

Figure 1. (A) Synthesis and morphological characterizations of Co-SA/P-in situ^[54]. Copyright 2020, American Chemical Society; (B) Schematic diagram of synthesized Fe-N/O-C^[55]. Copyright 2024, Wiley-VCH; (C) Typical CVD procedures to synthesize the Fe(Fc)-N/S-C catalyst^[56]. Copyright 2021, American Chemical Society; (D) Schematic illustration of the synthesis of the Fe₁-N₄SO₂/NC catalyst^[57]. Copyright 2025, American Chemical Society; (E) Schematic illustration and characterization of the Fe-N/Cl-C catalyst synthesized from HDPE^[58]. Copyright 2025, Wiley-VCH; (F) Schematic diagram of the synthesis route for SACs-Mn-1000@g-C₃N₄^[60]. Copyright 2021, Cell Press. SA: Single-atom; CVD: chemical vapor deposition; HDPE: high-density polyethylene; SACs: single-atom catalysts.