Room-Temperature-Fabricated Large-Area Catalysts for Ampere-Scale Seawater Oxidation

NiFe-based (oxy)hydroxides are widely recognized as the most active non-noble-metal oxygen evolution reaction (OER) catalysts, yet their application is constrained by poor stability under ampere-scale current densities and complicated, energy-intensive syntheses. Here, we introduce a one-step, room-temperature corrosion strategy applied to commercial stainless-steel mats to directly fabricate large-area MoO 4 2– -modified NiFe (oxy)hydroxide (Mo-NiFeOOH/SSM) electrodes. The incorporation of MoO 4 2– effectively regulates the electronic structure and charge distribution of NiFeOOH, which strengthens the adsorption of OER intermediates while suppressing the competitive adsorption of chloride ions. Combined with a porous, hydrophilic surface that facilitates electrolyte transport and bubble release, the electrodes exhibit robust corrosion resistance and high catalytic activity for seawater OER, sustaining operation at current densities of ≥1000 mA cm –2 . This facile, scalable, and low-cost fabrication method highlights the potential of Mo-NiFeOOH/SSM as a practical electrode design for large-scale seawater electrolysis.