Stable complete seawater electrolysis by using interfacial chloride ion blocking layer on catalyst surface

Seawater is the most plentiful natural resource we have on earth and new research looking for the alternative to the freshwater as seawater for hydrogen production by electrolysis. However, selective electrochemical anodic oxygen evolution reaction from seawater is challenging because of competitive chloride oxidation reaction as well as anodic corrosion. Here we report a FeOOH deposited β-Ni-Co hydroxide as a new active material with the outer graphene oxide layer, which effectively works for selective overall alkaline natural seawater splitting, it required a very low cell voltage of 1.57 and 2.02 V to reach current density 20 mA cm-2 and 1000 mA cm-2, respectively at 27 oC. Importantly, this electrolyzer shows exceptional stability for more than 378 h at 1 A cm-2 current density. This discovery can be generalized with other reported unstable OER/HER seawater splitting electrocatalyst, which can significantly progress in the expansion of seawater electrolysis for extensive hydrogen production.