Additionally, a closer inspection reveals the detailed structure of several NPs that include a Ptrich overlayer (Figure ; see also SI, Figures ). In addition, the observed width of the main X-ray diffraction (XRD) peaks (Figures ) correlates well with the TEM characterization. Furthermore, whereas majority of observed Pt-M NPs in the present samples contain most likely the (disordered) Fm-3m crystal phase, a small fraction of the intermetallic (ordered) phase is also observed with both TEM and XRD. In the case of 'A-activated' Pt-Cu catalyst (Figure ), a small amount R-3m (rhombohedral) characteristic for the 1:1 (PtCu) ratio is observed . On the other hand, A-activated Pt-Ni catalyst (Figure ) exhibits a small fraction of the tetragonal intermetallic crystal structure that is characteristic for the 1:1 (PtNi) ratio . In addition, it exhibits some leftover pure Ni phase that is still present even after the mild A-activation protocol. In contrast, A-activated Pt-Cu catalyst does not exhibit any pure Cu phase. Upon the exposure of both intermetallic catalysts to the harsher S-activation protocol we see two distinct changes in the case of S-activated Pt-Cu catalyst (Figure ). Firstly, the position of the most intense peaks at approximately 42 o and 49 o experienced a significant shift towards lower angles that correspond to a substantially more Pt-rich crystal structure.