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 (H 2 )‐based energy systems (e.g., storing wind power as H 2 ), 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 (O 2 ) evolution material, can be boosted by employing tungstate (WO 4 2– ) as the intercalated guest. Notably, insertion of WO 4 2− to LDH layers upgrades the reaction kinetics and selectivity, attaining higher current densities with ≈100% O 2 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, O 2 evolution follows lattice oxygen mechanism on NiFe LDH with intercalated WO 4 2− .