fig6
Figure 6. (A) Schematic illustration of the formation of xFe-SA/NPC-T samples; yellow and blue-grey balls represent melamine and the Fe-o-PD complex, respectively. Adapted with permission[23]. Copyright 2021, Elsevier; (B) The preparation scheme of the MgAl2O4/Ni-N-C. Adapted with permission[24]. Copyright 2024, Elsevier B.V. SA: Single-atom; NPC: N-doped porous carbon; T: pyrolysis temperature; o-PD: ortho-phenylenediamine.
