Hydrogen Production Based on Electrophysical Ionization of Water: A Comparative Analysis

Existing industrial methods of hydrogen production by water electrolysis are characterized by high specific energy consumption (3.9–4.1 kWh/m³ at j=1 A/cm², t=90 °C, U=1.65–1.72 V), which makes hydrogen fuel less competitive, as the cost of electricity accounts for up to 70% of its production cost. To achieve competitiveness, it is necessary to reduce specific energy consumption by at least 1 kWh/m³. This paper presents a comparative study of the energy efficiency of two alternative hydrogen production methods: electrophysical (EPI) and electrochemical ionization of water. EPI at low voltages (up to 29 V) and an electrochemical method based on the reaction of aluminum with water in the presence of sodium hydroxide (NaOH) were studied. It is shown that EPI is promising due to its operation at low voltage and reduced energy consumption. In the experiment, at U=10 V, electrode area of 17.55 cm², interelectrode distance of 1 mm, and current density of 3.4 mA/cm², 250 ml of hydrogen was obtained from 500 ml of water in 30 minutes. The calculated ionization depth was 3.11×10⁻⁸ cm, indicating the localization of the process in the near-electrode region and its significant potential for optimization. The electrochemical method (Al + NaOH) yielded 140–180 ml of hydrogen from 300 ml of water with 30 g of NaOH and 13–18 g of Al. The conducted analysis confirms that the electrophysical method is more energy-efficient compared to the investigated electrochemical method. Further optimization of EPI aimed at increasing the ionization depth and overall hydrogen yield could make this method competitive for the production of environmentally clean hydrogen.