Rare earth engineering to mitigate corrosion challenges in seawater electrolysis

As global demand for green hydrogen grows, scientists are exploring direct seawater electrolysis as a sustainable way to produce hydrogen without consuming scarce freshwater. Yet, seawater contains abundant chloride ions, which corrode electrodes and drastically shorten device lifetimes — a major barrier to commercialization.

A recent study by Shen et al., published in the Journal of the American Chemical Society (JACS, 2025), presents a promising breakthrough: a rare-earth oxide protection layer that shields seawater electrolyzers from chlorine corrosion while maintaining high hydrogen production efficiency.

Now, in a News & Highlights article in Frontiers in Energy, Prof. Yangming Lin and his colleagues provide a detailed overview and expert commentary on this innovation, emphasizing how rare-earth materials engineering could transform large-scale seawater-to-hydrogen technology.

A rare-earth shield against seawater corrosion

Shen’s team tackled the corrosion issue by coating iron–nickel sulfide electrodes with a thin layer of europium oxide (Eu₂O₃) — a rare-earth compound with a strong affinity for oxygen. This special coating creates a microenvironment rich in hydroxide ions (OH⁻), which discourages chloride ion (Cl⁻) adsorption and oxidation. As a result, it effectively blocks the corrosion pathway that normally plagues seawater electrolyzers.

Through advanced in situ experiments and computer simulations, the researchers demonstrated that the Eu₂O₃ layer not only resists chlorine attack but also enhances the oxygen evolution reaction (OER), a key step in hydrogen production. The modified electrodes achieved twice the current density of uncoated versions and remained stable for more than 1000 hours under high current operation.

Bridging fundamental chemistry and engineering

In their commentary, Prof. Lin and co-authors highlight that this approach exemplifies how materials design at the atomic level can solve practical electrochemical challenges. Significantly, multiple in situ electrochemical characterization techniques were integrated to cross-validate the interfacial evolution of key intermediate species, which fully supported the proposed reaction mechanisms, offering methodological insights for fundamental research in water/seawater electrolysis and broader electrochemical systems.

“Creating an OH⁻-enriched interface with rare-earth oxides provides a new direction for corrosion-resistant seawater electrolysis,” Prof. Lin notes. “This strategy not only stabilizes the electrode but also offers a scalable pathway toward efficient green hydrogen production in coastal regions.”

Promise and future outlook

Techno-economic analysis (TEA) from Shen’s study showed that the rare-earth-protected electrodes meet profitability targets for hydrogen generation, underscoring their potential for industrial deployment.

However, Prof. Lin’s team also points out remaining challenges: real-world seawater systems must operate for over 10,000 hours at ampere-level current densities. Further research is needed to confirm whether rare-earth coatings can sustain such demanding conditions and whether the process can be scaled up cost-effectively.

Even so, this research marks a significant advance in the quest to make seawater electrolysis — and thus large-scale green hydrogen — technically and economically viable.

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