fig4

Figure 4. DRT and in situ SRIR characterizations. DRT analysis of (A) Cu/NC and (B) Ax-Cl-Cu/NC at different voltages, Charge transfer resistance (RCT) plots of the catalyst under different applied potentials of Ax-Cl-Cu/NC and Cu/NC (C), in situ SRIR measurements at different potentials of (D) Cu/NC and (E) Ax-Cl-Cu/NC, (F) Intensity differences of ORR intermediate at Ax-Cl-Cu/NC and Cu/NC.