Nanointerface Coupling Activates Earth-Abundant Elements for Enhanced Oxygen Evolution Electrode Process

Understanding how compositional complexity influences electrocatalytic kinetics remains a major challenge in the design of multicomponent materials. The multifaceted interactions between constituent elements are able to obscure the factors governing kinetics of electrode processes. Here, we introduce a small compositional change to modulate the rate-determining step of the oxygen evolution reaction (OER) by tuning the binding energies of key intermediates. We combine advanced characterization, including in situ electrochemical X-ray absorption spectroscopy, with first-principles calculations to demonstrate that the drastic enhancement in OER activity of MnFeNi-based materials is driven by synergistic interactions among the constituent elements. This enhancement stems from targeted modulation of intrinsic reaction pathways, shifting the rate-determining step via controlled stabilization of key intermediates. Our findings introduce a clear viewpoint for understanding how compositional tuning governs kinetics in complex electrocatalytic systems, offering new design principles for next-generation electrochemical materials.