V ReaxFF predicts a sharp and almost vertical progression. We link this phenomenon to the experimentally observed place-exchange mechanism, where the oxidation starts to complete, and the nanoparticle evolves towards an oxide phase. This phenomenon was experimentally reported to occur at ≈ 1.05 V on platinum nanoparticles and surfaces. In our framework the event is transcribed via thermodynamic arguments and is due to the plateauing regime of the Gibbs free energies vs. oxygen ratio. In contrast, MACE-MP-0 predicts a more gradual increase in oxidation, most likely because it does not recognize the oxide phase formed by the ReaxFF forcefield. The potential reported by ReaxFF for the place-exchange mechanism (≈ 1.05 V) is in very good agreement with the reported experimental values. Results before the molecular dynamics (step 3) are also included to highlight the effects that the additional platinum-oxide clusters have on the predicted stability diagram. For ReaxFF we see that the curve is shifted towards lower potentials with the difference between the two curves becoming larger as the potential increases. MACE-MP-0 displays the inverted trend and smaller differences, as the forcefield does not predict the species. Being able to produce an accurate version of this curve is of paramount importance since oxygen population is suspected to be the cause of the high onset potential of the ORR on Pt for both thermodynamic and kinetic reasons. A catalyst that shifts this curve by 0.1 -0.2