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 MoO42–-modified NiFe (oxy)hydroxide (Mo-NiFeOOH/SSM) electrodes. The incorporation of MoO42– 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.