Boosting Direct Seawater Electrolysis through Intercalation Engineering of Layered Double Hydroxides

Abstract

Hydrogen production by water splitting directly from seawater is of great significance, where electrocatalysts with both high electrocatalytic activity and chlorine corrosion resistance have been long sought after. Herein, intercalation of Mo(VI) ions in NiFe layered double hydroxide (LDH) was engineered for boosting the electrocatalytic oxygen evolution reaction (OER). The intercalated Mo(VI) with high valence states facilitated NiFe LDH self-reconstruction through inducing the formation of Ni3+ sites; meanwhile, its volumetric and electrostatic repulsion synergistically inhibited the catalyst corrosion through excluding Cl– from intercalation. As a result, the in situ growth of Mo0.25-NiFe LDH on Ni foam required an overpotential as low as 335 mV to deliver 500 mA cm–2 in alkaline natural seawater with excellent stability for at least 500 h, being one of the top electrocatalysts so far as we know. Therefore, this convenient intercalation engineering provided a promising strategy for seawater splitting.