High Corrosion Resistance of NiFe‐Layered Double Hydroxide Catalyst for Stable Seawater Electrolysis Promoted by Phosphate Intercalation

Sustainable production of hydrogen from seawater electrolysis has attracted much attention in recent years. Considering that Cl- might corrode metal substrate by crossing through the covered catalyst, the conventional Ni(II)Fe(III)-layered double hydroxide (NiFe-LDH) loaded on metal substrate, as a favorable oxygen evolution catalyst, cannot be directly used for seawater electrolysis. Herein, an anti-corrosion strategy of PO43- intercalation in NiFe-LDH is proposed, in which the highly negatively charged PO43- in the interlayers can prevent the Ni substrate from Cl- corrosion by electrostatic repulsion. In order to verify the anti-corrosion effect, the two electrodes of the pristine NiFe-LDH and the PO43- intercalated NiFe-LDH are evaluated in a solution with high Cl- concentration. PO43- can effectively hinder the migration of Cl- between the interlayers of NiFe-LDH, thus the corrosion life of the PO43- intercalated NiFe-LDH is more than 100 times longer than that of the pristine NiFe-LDH. The improvement of stability is attributed to the inhibition effect of Cl- passing through the interlayers of NiFe-LDH, leading to the protection of Ni substrate. This work provides a design strategy for the catalysts loaded on the metal substrate, which has excellent Cl--corrosion resistance and can be widely used in hydrogen generation from seawater electrolysis.