Sites exhibiting lower deletion energies effectively act as reaction inhibitors, blocking the reaction, while higher energy sites suggests availability for further reduction. Figure suggests increasing site blocking as the oxygen ratio increases as supported by the decreasing 13 average deletion energy ⟨∆G del O ⟩ with increasing oxygen ratio. This decrease corroborates with the gradual formation of a stable oxide-like phase mentioned previously. Conversely, it is harder to add reactants due to the increase of ∆ ḠO in Figure . The two statements can be perceived as contradictory but are consistent with the Monte Carlo approach. As the simulation progresses, it is harder to add oxygen atoms, and the simulation converges to a specific atomic count. Similarly, weaker-bound atoms are deleted first, and the average deletion energy decreases. This observation indeed suggests that oxygen species do not uniformly act as site-blockers on the non-ideal Pt 353 nanoparticle. Rather, specific sites remain available for reduction, a phenomenon increasingly pronounced as the potential lowers. If we naively follow the CHE framework and consider the main condition for reduction to be ∆G del O > 2U then, at 0.8 V, 56% of species should be able to be reduced versus 35% for 0.87 V, and 9% for 1.07 V. Hence, it might be desirable to design catalysts which lower the presence of stable oxide-like species, without necessarily lowering the overall oxygen coverage. This can be done by finding a catalyst showing resistance to oxidation, therefore changing the slope of ∆ ḠO in Figure .