Fig. 7
a LSV curves of Fe-SAs/NSC (Fe-N4S2), Co-SAs/NSC (Co-N3S1), Ni-SAs/NSC (Ni-N3S1) and reference samples in O2-saturated 0.1 M KOH solution. b The calculated partial density of states (PDOS) of Fe-SAs/NSC (Fe-N4S2), Co-SAs/NSC (Co-N3S1), and Ni-SAs/NSC (Ni-N3S1). c Free energy diagrams of ORR on Fe-SAs/NSC (Fe-N4S2), Co-SAs/NSC (Co-N3S1), and Ni-SAs/NSC (Ni-N3S1). d Structural model of Fe-N3P1 site for ORR. e LSV curves of Fe-N/P-C-700 (Fe-N3P1), Fe-N-C-700 (Fe-N4), N/P-C-700, and Fe-N4@N/P-C-700 (Fe-N4) in O2-saturated 0.1 M KOH solution. f Free energy diagrams of ORR on Fe-N4 and Fe-N3P1 sites. g LSV curves of Co-N,B-CSs (Co-N3B1), Co/Co-N,B-CSs, Co-N-Carbon (Co-N4), and Pt/C catalysts in O2-saturated 0.1 M KOH solution. h, i Optimized geometry of the corresponding O2 adsorption configuration on Co-N,B-CSs (Co-N3B1). a–c Reproduced with permission from Ref. [106]. Copyright 2019, American Chemical Society. d–f Reproduced with permission from Ref. [110]. Copyright 2020, American Chemical Society. g-i Reproduced with permission from Ref. [112]. Copyright 2018, American Chemical Society