Modern platinum catalysts often consist of deposited platinum nanoparticles, which possibly exhibit complex structures that differ from their perfect counterparts. These structural differences can significantly influence the oxidation behavior and catalytic properties. The oxidation of these platinum nanoparticles has been extensively studied in the literature, with the formation of platinum-oxide phases reported in numerous studies. Saveleva et al. reported the growth of mixed PtO and PtO 2 layers when studying the electro-oxidation of Pt nanoparticles under applied voltage, at 450 K. Additionally Imai et al. characterized the initial platinum-oxide phase to have an α-PtO 2 local structure which transitioned to a β-PtO 2 structure as the oxidation time increased under sustained potential. The presence of an ordered oxide phase was confirmed by other studies under various experimental conditions, with a high dependence on the average particle size, where smaller particles were found to be more prone to oxidation. Figure : Experimentally reconstructed platinum nanoparticle used in this study. The nanoparticle consists of 353 atoms and was obtained from STEM images.