Mott–Schottky analysis for the oxide film formed spontaneously on Zn electrode as a function of the solution pH at 25 °C.

pH	V FB (V)	N D (cm−3)	δ (Å)
9.2	−0.017	1.81 × 1020	8.44
9.4	−0.040	1.97 × 1020	8.97
9.5	−0.077	2.29 × 1020	9.40
9.8	−0.282	11.80 × 1020	9.59