The redox potentials (U OH ) for the OH* reduction reaction (5) obtained from the TI calculations using the MLFF [via Eq. (17) in Methods] and the FP method [via Eqs. ( ), (17) and (19) in Methods] are shown in Fig. ), and FP denotes the FP results obtained by correcting the ML results using Eqs.( ), ( ) and (19). In (b), the previous calculations shown used the conventional FP method with harmonic oscillator models and structures optimized at 0 K. can provide reliable predictions for free energies of solid-liquid interfaces. In the following discussion, we focus on the FP results. To compare with the reported experimental results, the shifts in the redox potential (∆U OH = U OH -U Pt OH ) on the near-surface alloys Pt/Pt 1-x Cu x /Pt(111), relative to that on Pt(111), are presented in Fig. , as was done in the previous study. Similar to the previous FP calculation using the harmonic oscillator model and structures optimized at 0 K, our TI calculation indicates that the redox potential gradually increases with the amount of Cu (x) in the second layer from the surface [see the surface models in Fig. in Methods]. The calculation overestimates the extent of U OH increase compared to the experiment. This discrepancy arises because the elemental distribution in the experiment is not as ideal as in the model, and the atomic composition of the third layer in the calculated symmetrical slabs differs from that of the experiment.