Figure 2.

(a) Schematic representation of buffer reactions, pH gradient, and probed area SEIRA. (b) Experimentally measured and (c) simulated cathode surface pH as a function of phosphate buffer concentration and current density. (d) Current vs potential curve for different electrolyte concentrations (e) Experimentally measured cathode surface pH as a function of potential. All solutions are composed of equimolar H₂PO₄^– and HPO₄^2– mixtures. Shaded areas in b, c, e represent the buffering region that are relevant to local pH measurements.