When comparing the changes in these features for both A and S-activated catalysts respectively, unlike with the difference in the CO-electrooxidation maximum shift, no major difference distinguishing both activation protocols is revealed. Interestingly, the exact same 10 mV difference in the CO-electrooxidation peak maximum before and after PCA has been observed in the case of the d-Pt-Ni/C-JM benchmark (see SI, Figure ). However, similarly to both A and S-activated Pt-Ni catalysts, PCA again had no effect on the ORR polarization curves corresponding to their kinetic performances measured in half-cell TF-RDE before and after PCA (see SI, Figures S9b). ). Lastly, also the comparison of distinct features corresponding to the Pt-surface in the 2 nd and 50 th CV of the PCA (see SI, Figures and) reveals only slight changes for both A and S-activated Pt-Cu catalysts respectively. The take-away message here is that following our TF-RDE protocol, only a slight difference in the shift of the COelectrooxidation peak maximum provides a possible clue that the A and S-activated catalysts could in-fact be quite different despite exhibiting a similar ORR activity in TF-RDE.