Multicenter Electronic Interactions Driving Active Phase Formation in NiFe-MOFs for Anion-Exchange Membrane Water Electrolysis

Multimetal doping is widely employed to enhance oxygen evolution reaction electrocatalysis; however, the underlying mechanism remains poorly understood due to the complex interplay. Herein, we rationally integrate rare-earth Ce and transition-metal Ru into NiFe-MOFs (Ce,Ru-NiFe-MOFs) to achieve orbital complementarity between localized 4f and delocalized 4d states, thereby enabling a fundamentally distinct electronic regulation strategy beyond conventional charge transfer. This coupling effect fundamentally alters the dynamic evolution of the catalyst by accelerating the transformation of NiFe-MOFs into active NiFeOOH species. We further demonstrate that Ce/Ru codoping induces oxygen-bridged multicenter orbital coupling (3d-4d-4f), as evidenced by soft- and hard-X-ray absorption spectroscopy and aberration-corrected high-angle annular dark-field scanning transmission electron microscopy, together with density functional theory calculations, thereby establishing nonadditive electronic interactions and multilevel electron-transfer pathways. Consequently, the reconstructed catalyst exhibits an optimized electronic structure with enhanced OH- adsorption, suppressed proton-induced corrosion, and reduced energy barrier for the rate-determining step. Therefore, the catalyst delivers an overpotential of 199 mV at 10 mA cm-2 and outstanding durability exceeding 1600 h at 400 mA cm-2. Additionally, when integrated into an anion-exchange membrane water electrolysis system, it achieves a low cell voltage of 1.747 V at 1000 mA cm-2 (meeting the U.S. DOE 2026 target) and maintains stable operation for over 95 h at 500 mA cm-2. This work establishes a clear mechanistic framework linking orbital-level coupling, reconstruction kinetics, and catalytic performance, and provides a general design principle for engineering advanced electrocatalysts via multicenter orbital interactions.