fig9

Figure 9. (A) HAADF-STEM image of Cu-S-Ni/SNC. The dual-atom sites and single sites were circled with dotted yellow line and red line, respectively; (B) 3D model of Cu-S-Ni sites along the region of 1 in (A); (C) Density profiles of Cu-S-Ni and single-atom sites in the HAADF-STEM^[75]. Copyright 2024, Wiley-VCH; (D) HAADF-STEM image of Fe-Zn@SNC; (E) Kernel method of frequency statistic and Gauss fitting of diatomic distances obtained from all the yellow circles in (D)^[97]. Copyright 2023, Wiley-VCH. HAADF-STEM: High-angle annular dark-field scanning transmission electron microscopy; SNC: sulfur- and nitrogen-co-doped carbon.