The three pieces of capacitance data are fitted with the present model in Figure The pure double-layer capacitance 𝐶 dl is around 20 μF cm -2 , which is close to the value obtained from EIS by Pajkossy and Kolb. 𝐶 dl has a broad peak around the pzc. This non-GCS feature is attributed to the chemical and electrostatic interactions of the first water layer with the metal, as explained in the discussion around Figure . 𝛿𝜇 ̃= -2.5 is used for this case, in line with the AIMD results that the first water layer with the O-down configuration is more stable at an uncharged Pt(111) due to chemical interactions. The measured capacitance 𝐶 total is contributed majorly by adsorption capacitances 𝐶 H ad and 𝐶 OH ad .