To explore the effect of electronic charge, we performed calculations on clean and oxidized electrodes over a surface charge density range of -5 µC/cm 2 to +5 µC/cm 2 , in increments of 1 µC/cm 2 . This range was chosen by conducting prior calculations to determine the relevant potential range for the ORR, i.e. between 0.3 V and 1.3 V. The water O-site and H-site density profile changes are presented in Figure .