Ultrasonic wave field effects on hydrogen production by water electrolysis

Abstract

In this paper, Electrochemical impedance spectroscopy (EIS) was used to examine polarization impedance phenomena in ultrasonic water electrolysis. The method has been used previously for electrochemical analysis of fuel cells, corrosion, electroplating, etc. However, the EIS method and curvilinear regression have never been used before to analyze the electrochemical reactions which take place during water electrolysis. This study found that when a 2 V potential was applied, the ultrasonic wave field improved activity impedances and concentration impedances and accelerated the rising of hydrogen bubbles during water electrolysis. Ultrasonic power, electrode gap, and electrolyte concentration were the key parameters that affected water electrolysis. At normal temperature, when the electrode gap was 2 mm, the potential 4 V, and electrolyte concentration 40 wt%, the difference in current density between electrolysis without ultrasonic power and electrolysis with ultrasonic power of 225 W was 240 mA/cm². Deducting the power needed for the ultrasonic wave showed an power savings of 3.5 kW and an economical power efficiency of 15%.

Keywords:

• EIS
• water electrolysis
• ultrasonic
• impedance