The central objective of this study is to precisely calculate the redox potential U OH of the OH* reduction to water using finite-temperature MD simulations that can account for interfacial solvation effects, with the assistance of MLFFs. However, before explaining the MD method, we begin by explaining how U OH is related to the catalytic activity of the ORR. To achieve this, we begin with a simple kinetic model of the ORR proposed by Rossmeisl and coworkers, which is well-known for its excellent ability to reproduce the trend in catalytic activity of the ORR across a wide range of materials, 19 using a single property of the catalyst, specifically U OH , as shown in Fig. . This model employs three assumptions. First, the ORR is assumed to be limited by either the HO 2 formation reaction (2) or the OH* removal reaction (5). This assumption has been supported by more refined kinetic models and experiments. Second, the contribution of the backward reaction (2) is negligible due to the large overpotential under which the ORR occurs. Third, the catalyst that stabilizes OH* is assumed to stabilize HO 2 * by the same energetic extent, due to a property known as the scaling relation. This relation has also been validated by FP calculations for various catalysts. Based on the first and second assumptions, the steady-state ORR current density j can be simply written as