From Atomic-Scale Engineering to Industry-Ready Systems: Prospects for Seawater Electrolysis Toward Hydrogen.

To accelerate the industrial application of hydrogen (H2) and support the global energy transition, seawater electrolysis emerges as a promising strategy to address energy demands and freshwater scarcity. Owing to its natural abundance and high ionic conductivity, seawater represents an attractive electrolyte resource. However, its complex chemical composition introduces significant challenges, including sluggish kinetics, catalyst poisoning, chlorine evolution, membrane degradation, and long-term corrosion. Recent years have witnessed significant progress in electrocatalyst development, electrolyzer design, and mechanistic understanding aimed at overcoming these seawater-specific constraints. In this review, we provide a comprehensive and critical overview of advances in seawater electrolysis, covering electrocatalyst design strategies for the hydrogen evolution reaction, oxygen evolution reaction, and bifunctional reactions, as well as developments in device architectures and operations. Emphasis is placed on scalable synthesis, stability under real seawater conditions, and theoretical insights from density functional theory calculations into reaction pathways and degradation mechanisms. In addition, key challenges related to standardized testing protocols, system integration with renewable energy sources, and techno-economic viability are discussed. Finally, future perspectives are outlined to guide the design of durable, scalable, and economically feasible seawater electrolysis systems, highlighting critical research directions to accelerate the transition toward large-scale green H2 production.