Investigating sono-electrolysis for hydrogen generation and energy optimization

Abstract

Hydrogen (H2) is expected to be the new fuel generation, surpassing conventional fossil fuels and coal in reducing carbon emissions. However, green H2 production constitutes only a minor part of the H2 production sector. Water electrolysis is a method for green H2 production but suffers from low energy efficiency. Auxiliary ultrasound in H2 production is a method under research for increasing H2 production and energy efficiency. This study evaluates the effectiveness of H2 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 H2 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 H2 production increase with ultrasound power. The H2 production for electrolysis reaches an optimum condition at 129.5 cm3/h with an energy efficiency of 13.15 %, while high-power sono-electrolysis produces H2 at 265 cm3/h with an energy efficiency of 7.71 % at the optimum condition. Ultrasound increases H2 production in electrolysis but reduces energy efficiency. A more detailed exploration of electrolysis and sono-electrolysis is still needed to achieve high H2 production with high energy efficiency.