Harvesting energy from marine: Seawater electrolysis for hydrogen production

Hydrogen, as a promising secondary energy source, plays a crucial role in the global energy transition. Hydrogen production via water electrolysis is pivotal for advancing the hydrogen energy economy. Seawater, a vast hydrogen resource, presents significant potential for large-scale hydrogen production through electrolysis. However, the intricate composition of seawater and undesirable competitive reactions pose challenges to the efficiency and sustainability of seawater electrolysis for hydrogen production. Therefore, devising efficient and stable strategies for hydrogen production is of immense significance. This review provides a concise overview of the fundamental principles governing hydrogen evolution from water and seawater electrolysis. Additionally, rational design strategies for viable cathodes to achieve large-scale and sustainable hydrogen production are emphasized. An extensive assessment of alkaline electrolyzers, solid polymer electrolyzers, solid oxide electrolyzers, and hybrid electrolyzers was conducted to identify the most reliable electrocatalytic systems for hydrogen production. Furthermore, advanced seawater electrolysis systems that exceed theoretical voltage and power consumption limits are highlighted. Finally, the review outlines existing challenges, development directions, and prospects, aiming to enhance the development of efficient, stable, and selective technique for seawater electrolysis.