Water electrolysis in the presence of an ultrasonic field

The energy efficiency of water electrolysis has been considerably improved in the presence of an ultrasonic field. This was demonstrated by measuring the cell voltage, efficiency and energy consumption of the generated gas from the electrolysis. These measurements were carried out in alkaline solution using linear sweep voltammetry (LSV) and galvanostatic polarization techniques. A large reduction of the cell voltage was achieved under the ultrasonic field, especially at high current density and low electrolyte concentration. With the same current density, the cell voltage difference with and without the ultrasonic field fell as the concentration of the electrolyte was increased. The efficiency of H2 generation was improved at a range of 5–18% at high current density in the ultrasonic field but the efficiency of O2 generation fell a little due to the difference in the behavior of the gas bubbles. The energy saving for H2 production by using the ultrasonic field was about 10–25% for a certain concentration of the electrolyte when a high current density was used. On the other hand, the energy consumption for O2 production with and without the ultrasonic field was almost the same.