Here, we briefly explain how the thermodynamic stability of OH*, which is the governing factor of ORR activity shown in Fig. , specifically the redox potential U OH of reaction (5), is calculated using the ML-aided TI method. We also describe how the changes in OH* stability due to melamine modification or alloying of Pt appear in the TI calculations. The redox potential U OH is given as follows (see Methods for the derivation):