fig11

Figure 11. (A) LSV curves of Pt/C. (B and C) Differential charge density analysis of SA Fe/NC and SA Fe@ZrO₂/NC models. Light blue area represents charge density decrease, and yellow area denotes charge density increase^[168]. (D) LSV curves of the catalysts for the ORR. (E) ORR curves of the Fe-N-C/Nb₄C₃T_x (2:1) before and after sweeping for 2,000 cycles. (F) Chronoamperometric curves of the catalyst based on the Fe-N-C/Nb₄C₃T_x (2:1)^[169]. (G) ORR polarization curves. (H) j_k and TOF of catalysts to present intrinsic activity. (I) Durability results of the catalyst after 50,000 potential cycles^[170].