In total, for both electrolysis voltages, a homogeneous Au oxide film is formed on the entire Au POSC. Only for 30 s HV electrolysis at 300 V, the Au oxide film is less homogeneous or exfoliates from the flat Au(111) and Au(100) regions as well as in the Au(111*) region. The origin of the crack formation can at this point not be explained. Possible reasons could be the difference in Au oxide thickness obtained for long electrolysis times or the differences in processes occurring at the electrodes at both voltages (electrolysis with bubble formation or plasma). It is also possible that the thick Au oxide film formed after 30 s HV electrolysis is disrupted upon emersion of the electrode from the electrolysis solution.