As the applied potential increases, the pH within the CEL decreases significantly due to the generation of H + via water dissociation and bicarbonate dissociation. Consistent with the equilibria presented in equations ( )-( ), as the pH in the CEL decreases, the concentrations of OH -, CO3 2-, and HCO3 -decrease, and the concentration of CO2 in the CEL increases. Additionally, diffusion gradients manifest in K + to maintain electroneutrality with the water-dissociationgenerated H + . Importantly, the model enables spatial resolution of in-situ CO2 regeneration, which is shown to occur only at the CEL|cBL interface, because the concentration of (bi)carbonates are too small within the CEL itself (due to Donnan exclusion) to facilitate reaction with waterdissociation-generated H + . The H + from water dissociation exits out of the CEL and reacts with HCO3 -in the electrolyte to form CO2 that reaches its solubility limit, becomes saturated, and bubbles out, as is consistent with the experimental visual observation (Supporting Video S1) and prior studies of BPMs operated in KHCO3 solutions. On the AEL side, pH increases do not occur as readily with increasing cell potential, because the AEL is fully (bi)carbonate exchanged at equilibrium and the presence of (bi)carbonates in these high (~1-2 M) concentrations buffer changes in pH and pOH. This is important to note, because the pH gradient in these systems is typically assumed to be directly proportional to the electrostatic potential profiles (Figure -23). However, these results demonstrate that the weak-acid buffer breaks the scaling relationship between the applied potential and the developed pH gradient by competitively consuming generated OH -anions.