Tungstate Intercalated NiFe Layered Double Hydroxide Enables Long‐Term Alkaline Seawater Oxidation

Abstract

Renewable electricity-driven seawater splitting presents a green, effective, and promising strategy for building hydrogen (H₂)-based energy systems (e.g., storing wind power as H₂), especially in many coastal cities. The abundance of Cl^- in seawater, however, will cause severe corrosion of anode catalyst during the seawater electrolysis, and thus affect the long-term stability of the catalyst. Herein, seawater oxidation performances of NiFe layered double hydroxides (LDH), a classic oxygen (O₂) evolution material, can be boosted by employing tungstate (WO₄ ^2-) as the intercalated guest. Notably, insertion of WO₄ ^2- to LDH layers upgrades the reaction kinetics and selectivity, attaining higher current densities with ≈100% O₂ generation efficiency in alkaline seawater. Moreover, after a 350 h test at 1000 mA cm^-2, only trace active chlorine can be detected in the electrolyte. Additionally, O₂ evolution follows lattice oxygen mechanism on NiFe LDH with intercalated WO₄ ^2-.