Seawater Electrolysis Sustained via the Permselective Layer on Catalysts

Seawater electrolysis is a sustainable strategy to produce green hydrogen but necessitates robust anodes capable of resisting chlorine corrosion and side reactions. Here, we design the conformal phosphate coating on nickel–iron molybdate microrods as an ion-selective permeable layer to sustain alkaline seawater oxidation against chlorine attack even at ampere-level high current densities. Insights into the chemical microenvironment shed light on the roles of surface phosphates both in repelling chloride ions and facilitating hydroxyl diffusion to sustain the high-flux oxygen evolution reaction. This surface-phosphated microrod anode catalyzes stably alkaline seawater oxidation at a high current density of 1 A cm –2 for over 700 h without corrosion. Using such an anode in an actual electrolyzer, we demonstrate seawater electrolysis at 0.5 A cm –2 sustained for 500 h at 2.0 V, with an electricity consumption of 4.78 kW h Nm –3 and a cell efficiency of 74%.