The predicted values of ∆ ḠO using MACE-MP-0 are shown in Figure for the 31 configurations. We find the descriptor ∆ ḠO to highly depend on the oxygen ratio, with the slope of the curve directly giving the lateral interaction coefficient ξ O . This coefficient is expected to be small at low oxygen ratios, and to progressively increase as oxygen content increases due to modification of the electronic structure of the nanoparticle, and direct interactions between oxygen atoms. We report a similar behavior until an oxygen ratio of ≈ 0.7, after which the quantity steadily decreases, in relation with the plateauing behavior of the Gibbs free energy at higher oxygen ratios. We could not find reports of such decreasing lateral coefficients in the literature, which are typically reported for varying surface coverages of adsorbates on idealized surfaces, significantly differing from the systems investigated in this work. Yet, the range obtained for the lateral coefficient is in good agreement with the expected values for ORR intermediates with values of 0-20 kJ/mol predicted for OH * . This decrease in lateral coefficient paradoxically suggests that beyond a certain oxygen ratio threshold, the addition of oxygen atoms occurs with diminished resistance. In a recent work, we attributed this phenomenon to the initiation of a stable oxide-like phase at higher oxygen ratios, i.e. as the oxygen content surpasses a critical level, the electronic structure of the Pt skeleton begins to transition, altering the energetics of oxygen incorporation. Figure : Oxygen Gibbs free energy ∆ ḠO per atom (blue circles) and lateral coefficient ξ O (red dashed line). The fitting was done using a generalized error function. The red curve is the direct derivative with respect to the oxygen ratio.