Synergistic d ‐Orbital Interactions and Interfacial Coupling in Metal–Organic Framework‐Based Electrocatalysts for Direct Seawater Electrolysis

The structural versatility of metal–organic frameworks (MOFs) makes them attractive platforms for electrocatalyst design, but with limited active site density. Here, Fe‐MOF is decorated with Ni‐, Mo‐, and W‐based oxides via electrochemical deposition, avoiding high‐temperature carbonization. The short interlayer distances (1.88–2.67 Å) and more negative binding energies (−4.09 to −4.88 eV) indicate intimate interfacial contact and strong adhesion between the deposited metal oxides and the Fe‐MOF. Synergistic interactions between Ni 3 d and Mo/W non‑3 d orbitals modulate electronic structure and optimize adsorption of reaction intermediates. Electron localization values <0.5 and charge density difference analysis reveal substantial electron redistribution and interfacial charge transfer. DFT studies show that NiMoW@Fe‐MOF with the lowest ɳ _OER (0.68 V) preferentially adsorbs OH ⁻ over Cl ⁻ (−1.14 and −1.09 eV, respectively), promoting selective OER. The NiW@Fe‐MOF (cathode) exhibits the most favorable Δ G _H * (−1.64 eV) and suppresses Ca(OH) ₂ and Mg(OH) ₂ precipitation via WO ₂ ‐mediated OH ⁻ consumption. Consequently, the NiW@Fe‐MOF‖NiMoW@Fe‐MOF enables selective inhibition of chlorine evolution and mitigation of scaling. The NiW@Fe‐MOF‖NiMoW@Fe‐MOF operates stably in alkaline seawater at 0.5 A cm ⁻² for 500 h and delivers 1 A cm ⁻² at 1.84 V, well below the 2.35 V required by a 20% Pt/C‖RuO ₂ benchmark, demonstrating strong potential for direct seawater splitting.