Determination of the pzc at solid electrodes with a dropping electrolyte electrode

The determination of the pzc at solid electrodes requires indirect approaches based on capacitance measurements or thermodynamic methods, exploiting physical changes related to double layer structure, like contact angle, adsorption etc. The proposed approach is based on the measurement of the transient charging current flowing, on exposure, at the surface of a solid electrode. The system consists of a static electrode facing upward; an electrolyte solution drops onto the electrode surface from a capillary situated above it. Between drops, the electrode surface is dried by a continuous stream of nitrogen. Potentiostatic conditions are established as soon as the metal electrode is re-wetted and the charging current measured. The pzc is characterized by the absence of the charging current.