Long‐term Durability of Seawater Electrolysis for Hydrogen: From Catalysts to Systems

Direct electrochemical seawater splitting is a renewable, scalable, and potentially economic approach for green hydrogen production. However, issues related to low durability caused by complex ions in seawater pose great challenges for its industrialization. In this review, a mechanistic analysis of durability issues of electrolytic seawater splitting is discussed. We critically analyze the development of seawater electrolysis and identify the durability challenges at both the anode and cathode. Particular emphasis is given to elucidating rational strategies for designing electrocatalysts/electrodes/interfaces with long lifetimes in realistic seawater including inducing passivating anion layers, preferential OH- adsorption, employing anti-corrosion materials, fabricating protective layers, immobilizing Cl- on the surface of electrocatalysts, tailoring Cl- adsorption sites, inhibiting binding of OH- to Mg2+ and Ca2+, inhibiting adherence of Mg and Ca hydroxide precipitation, and co-electrosynthesis of nano-sized Mg hydroxides. Synthesis methods of electrocatalysts/electrodes and innovations in electrolyzer are also discussed. Furthermore, the prospects for developing seawater splitting technologies for clean hydrogen generation are summarized. We found that researchers have changed the attitude towards Cl- ions from "hate" to accept to utilize, as well as more attention to cathodic reaction and electrolyzers, which is conducive to accelerate the commercialization of seawater electrolysis.