Hydrogen overvoltage effects with

The catalytic effect of the electrode material on the branching of an electrode reaction is most often apparent at cathodes with low overvoltage but may also be observed at materials with high hydrogen overvoltage. In the reduction of acetone in 6 N H2SO4 at a platinized platinum electrode, two independent paths are accessible One leads to propane and the other to isopropyl alcohol. The rate of formation of these two products depends on the voltage and on the history of the electrode. 

At present, electrolysis cells basically consist of two electrodes separated by an asbestos diaphragm impermeable to gases. 20 to 30% potassium hydroxide is dissolved in the electrolyte to increase its conductivity. The electrolysis is carried out at 80 to 85°C. The theoretical decomposition potential is 1.24 V with 1.9 to 2.3 V being used in practice due to overvoltage effects etc. Oxygen is produced at the anode and hydrogen at the cathode ... 

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