Hydrogen's potential as a clean energy source is highlighted through electrolytic seawater splitting, which converts ocean-sourced renewable energy into hydrogen without greenhouse gas emissions. Challenges in direct seawater electrolysis, like the ClOR hindrance, are addressed with corrosion-resistant electrocatalysts. Alternative strategies involve novel anodic reactions and decoupled electrolysis with redox mediators to improve efficiency and stability. The DSDE system proposes a unique approach by integrating a redox-flow electrolysis cell with an O2 reactor, preventing ClOR occurrence and chlorine byproducts. Operational results show low voltages, stability, and performance in Cl--saturated seawater, paving the way for more sustainable and cost-effective hydrogen production.