fig1

Figure 1. Synthesis and morphological characteristics of the Fe-N-C. (A) Schematic illustration of the fabrication procedures of the Fe-N-C; (B-D) Characterizations of Fe-N-C. (B) SEM images, (C) TEM images, (D) EDS elemental mappings and (E) HAADF-STEM image of Fe-N-C-2; the red circle represents single Fe atom. SEM: Scanning electron microscopy; TEM: transmission electron microscopy; EDS: energy dispersive X-ray spectroscopy; HAADF-STEM: high-angle annular dark field- scanning transmission electron microscopy.