fig3

Figure 3. (A-C) SEM images. (D and E) TEM and HRTEM images of Ni-N-C. (F and G) TEM and HRTEM images of Fe-N-C. (H and I) TEM and HRTEM images of Fe/Ni-N-C. (J) HRTEM images for the (111) planes of Ni of Ni-N-C, HRTEM images for (110), (111), and (110) planes of Fe, FeN, and Fe₂O₃ of Fe-N-C, HRTEM images for (111) and (103) planes of FeNi₃ and Fe₃O₄ of Fe/Ni-N-C. (K) EDS mapping images of Fe/Ni-N-C.