Investigating sono-electrolysis for hydrogen generation and energy optimization

Hydrogen (H 2 ) is expected to be the new fuel generation, surpassing conventional fossil fuels and coal in reducing carbon emissions. However, green H 2 production constitutes only a minor part of the H 2 production sector. Water electrolysis is a method for green H 2 production but suffers from low energy efficiency. Auxiliary ultrasound in H 2 production is a method under research for increasing H 2 production and energy efficiency. This study evaluates the effectiveness of H 2 production with auxiliary ultrasound under various parameters of temperature (28–45 °C), solution concentration (15–45 %), voltage (3.5–10 V), and ultrasound power (silent, low, and high) for electrolysis and sono-electrolysis. The result shows that sono-electrolysis benefits from increased H 2 production compared to electrolysis when voltage, temperature, solution concentration, and ultrasound power increase. However, the energy efficiency for sono-electrolysis is lower than that for electrolysis under all conditions due to inefficient ultrasound power transmitted and low H 2 production increase with ultrasound power. The H 2 production for electrolysis reaches an optimum condition at 129.5 cm 3 /h with an energy efficiency of 13.15 %, while high-power sono-electrolysis produces H 2 at 265 cm 3 /h with an energy efficiency of 7.71 % at the optimum condition. Ultrasound increases H 2 production in electrolysis but reduces energy efficiency. A more detailed exploration of electrolysis and sono-electrolysis is still needed to achieve high H 2 production with high energy efficiency.