Ultrafast Reconstruction of Ni‐Based Alloy Precatalyst for Robust Seawater Oxidation

Abstract NiOOH, typically generated through prolonged electrochemical reconstruction of precatalysts such as Ni‐based compounds, is highly active for electrochemical seawater oxidation but suffers from limited durability. In this study, NiMo alloy precatalyst is designed to rapidly reconstruct into active NiOOH for seawater oxidation at industrial current densities with exceptional durability. During anodic polarization, Mo in the as‐produced precatalyst undergoes dealloying, creating a favorable microenvironment that accelerates the conversion of Ni to NiOOH within just two cyclic voltammetry cycles. Residual Mo tunes the electronic configuration of NiOOH, enhancing its activity, while leached Mo is oxidized and forms MoO 4 2− , repelling corrosive Cl − in seawater from the active sites. The reconstructed catalyst achieves a current density of 500 mA cm −2 at an overpotential of 288 mV for up to 1000 h in 1.0 m KOH alkalized seawater. When integrated into an anion exchange membrane electrolyzer, it delivers an industrial current density of 1000 mA cm −2 at a cell voltage of only 1.78 V, with a power consumption of only 4.25 kWh m −3 . The obtained results demonstrate the significant potential of the developed catalyst for practical applications in green hydrogen production from seawater.