Applying an external
potential difference between two
electrodes
leads to a voltage drop in an ion conducting electrolyte. This drop
is particularly large in poorly conducting electrolytes and for high
currents. Measuring the electrolyte potential is relevant in electrochemistry,
e.g., bipolar electrochemistry, ohmic microscopy, or contact glow
discharge electrolysis. Here, we study the course of the electrolyte
potential during high voltage electrolysis in an electrolysis cell
using two reversible hydrogen electrodes as reference electrodes,
placed at different positions in the electrolyte. The electrolysis
is performed with a Pt working and stainless steel counter electrode
in a KOH solution. A computational COMSOL model is devised which supports
the experimentally obtained potential distribution. The influence
of the cell geometry on the electrolyte potentials is evaluated. Applying
the knowledge of the potential distribution to the formation of a
Au oxide surface structure produced during high voltage electrolysis,
we find that the amount of oxide formed is related to the current
rather than the applied voltage.