As observed in the case of WPW cycles (0.05-1.4 VRHE, 5 mV s -1 , 0.1 M HClO4; Figures ; see also SI, Figure ), one can expect two typical transient Pt dissolution peaks . Usually, this includes a smaller peak corresponding to the anodic (A1) and a more dominant cathodic (C1) Pt dissolution. Anodic (A1) Pt dissolution mechanism involves surface structure roughening caused by oxide place exchange mechanism. This creates Pt defects (low coordination sites), which do not get passivated by oxide formation and are thus prone to dissolution . On the other hand, with further penetration of oxygen in the crystal lattice of the NPs, reduction of this Pt-oxide results in formation of a much larger amount of unstable Pt defects, leading to a significant cathodic (C1) dissolution . Furthermore, what seems to be a general feature for all Pt-alloys 41 is that following both the A1 and C1 Pt dissolution, we also observe A1' and C1' less noble metal dissolution. In other words, every time Pt dissolves, this exposes previously protected M atoms and causes their subsequent dissolution . In addition to that, Pt-alloys usually also exhibit another peak related to the less noble metal dissolution (A2'). However, what is special in this case is that A2' does not have a corresponding Pt dissolution peak such as A1' and C1'. For instance, A2' Cu dissolution peak (Pt-Cu alloy;