This indicates that the potential of the sulfonate desorption peak on the RHE scale does not shift with the electrolyte pH because the sulfonate coverage is fixed at the peak potential. This is consistent with the observed lack of peak shift during sulfonate desorption in electrolytes with pH ranging from 1 to 3 on the RHE scale (Figure , Table ). We note that the analysis above is in complete agreement with that when the Donnan potential is explicitly accounted for, i.e., the lack of dependence of the sulfonate desorption peak on electrolyte pH on the RHE scale is caused by the concomitant shifts of the Donnan potential and the RHE potential on the absolute potential scale.