Oxygen Reduction Reaction on Single-Atom Catalysts from Density Functional Theory Calculations Combined with an Implicit Solvation Model

We present a computational study of the electrochemical oxygen reduction reaction on single metal catalysts embedded in nitrogen-doped graphene, namely, TM-N4-C (TM＝Fe, Co), using density functional theory calculations combined with the effective screening medium method and the reference interaction site model. We systematically investigated the roles played by solvent, electrolyte (pH), and electrode potential in the electrochemical oxygen reduction reaction on TM-N4-C. Furthermore, by performing constant-potential calculations, we were able to obtain the limiting potentials/overpotentials, in better agreement with the experimental values than those obtained with the constant-charge (neutral) calculations, demonstrating the importance of the constant-potential calculations of the electrochemical reactions.