Electron‐Deficient Mn Sites Functionalized with Ag Nanoclusters Enable Selective and Durable Seawater Oxidation

Abstract Direct seawater electrolysis presents significant challenges due to chloride‐induced corrosion and the competitive Cl − oxidation, which undermines the efficiency and durability of anode materials. In this study, the rationally synthesized Ag nanocluster‐decorated calcium–manganese borate (AgNCs@Ca–MnB) nanosheets are reported as a highly efficient and corrosionresistant electrocatalyst for oxygen evolution in alkaline seawater. Incorporating boron into the Ca─Mn lattice creates electron‐deficient sites that enhance the covalency of Mn─O bonds, promoting favorable adsorption energies for OER intermediates while stabilizing the catalyst structure under oxidative conditions. Ag nanoclusters are strategically introduced to the surface, functioning as selective Cl − traps through Ag─Cl complexation, effectively suppressing the Cl − oxidation pathway. The hybrid design further boosts electrochemical surface area and electronic conductivity, ensuring high current density operation with minimal degradation. The AgNCs@Ca–MnB catalyst achieves an overpotential of ≈310 mV at 10 mA cm − 2 in real seawater and demonstrates exceptional operational stability over 100 h, outperforming many reported transition metal‐based systems. This study introduces a synergistic strategy combining boron‐induced electronic modulation and silver‐mediated chloride immobilization, offering a new direction in designing durable and selective seawater oxidation catalysts.