However, we noticed that the simulated activity is approximately three times higher than the experimental data, which cannot be explained by Frumkin effects. Therefore, we suggested that specific EDL effects beyond Frumkin corrections are likely responsible for this. By incorporating the surface charging effect on adsorption energies of formate, the model captures the experiments quantitatively in both perchlorate solution (Figure ) and phosphate solution. For the H2O2 redox reaction, pH effects were shown to arise from the pH-dependent surface charging effect, which were studied using AIMD at electrified Pt(111)-water interfaces. The negative and positive surface charge conditions were simulated by introducing a lithium ion and a fluorine ion in the water layer, respectively. It was revealed that the negative surface charge repels the O-O bond of H2O2 farther away from the electrode surface, leading to a higher activation barrier for breaking the O-O bond. When the applied potential shifts negatively, the driving force of HPRR increases, which leads to the decrease of the activation barrier and thus promotes the activity. Concurrently, the surface charge becomes more negative, increasing the activation barrier and suppressing the reaction. These two competing effects cause the nonmonotonic (first increasing and then decreasing) activity of HPRR with the negative shift of electrode potential. The activity suppression effect caused by negative surface charge is also responsible for the pH effects of HPRR. As the surface charge becomes more negative with increasing pH, the onset of the suppression effect shifts to more positive potential for higher pH.