Besides, the adsorption free energies of the ORR intermediates were computed through the following reactions, respectively, where H2(g) and H2O(g) were taken as references (vide infra for the explanation on the choice of these intermediates). By doing so, we avoid using O2(g) as a reference species for which the bond energy in the triplet is not well-described using DFT. 14 * +2