From the abstract of the linked Nature article[0]: > This is achieved by introducing a Lewis acid layer (for example, Cr2O3) on transition metal oxide catalyst

From the abstract of the linked Nature article[0]: > This is achieved by introducing a Lewis acid layer (for example, Cr2O3) on transition metal oxide catalysts to dynamically split water molecules and capture hydroxyl anions. Such in situ generated local alkalinity facilitates the kinetics of both electrode reactions and avoids chloride attack and precipitate formation on the electrodes. For all the hype about "untreated seawater", I have to assume they're at least running it through a mesh to get the larger contaminants out. [0] https://www.nature.com/articles/s41560-023-01195-x https://www.nature.com/articles/s41560-023-01195-x