Figure shows the 𝐶 dl , adsorption capacitance (𝐶 ad ), and their sum for this case. 𝐶 ad exhibits a peak starting from 0 V and ending at 0.5 V referenced to 𝐸 pzc,SHE 0 . The location and shape of 𝐶 ad will change if a different distribution function 𝑓 OH (𝐸) is used in Eq. (10). Interestingly, 𝐶 dl is changed in the presence of chemisorption. 𝐶 dl of the case with and without chemisorption is compared in Figure . It is clearly seen that the chemisorption leads to a new valley of 𝐶 dl . The depth of the valley can be tuned by the net charge number of adsorbates γ. A smaller γ leads to a more shallow valley with all positive-valued 𝐶 dl , while a larger γ leads to a deeper valley with negative-valued 𝐶 dl . Negative 𝐶 dl means that σ free decreases with increasing the electrode potential, resulting in a nonmonotonic surface charging behavior. Chemisorption-induced nonmonotic surface charging behaviors were revealed in a previous work, and elucidated in a, hopefully, more accessible manner recently by this writter. The basic idea, as expressed in Eq.( ), is that negatively charged chemisorbed OH introduce a potential drop Δ𝜙 ad , which is tantamount to increasing the pzc. As a result, σ free increases at a lower rate with the electrode potential, namely, a smaller 𝐶 dl , or decreases with the electrode potential, namely, a negative 𝐶 dl , depending on the magnitude of 𝜇 OH .