Fe-Mediated Destabilization of Oxygen Intermediates Boosts Oxygen Evolution in Multimetallic Layered Double Hydroxides

초록

Rational design of efficient and robust electrocatalysts for the oxygen evolution reaction (OER) is essential for advancing electrochemical water splitting systems. In this work, we report an Fe-incorporated NiCo layered double hydroxide (NiCoFe-LDH) nanosheet array grown directly on three-dimensional (3D) nickel foam via a facile hydrothermal route. Among the various compositions investigated, optimized NiCoFe-LDH exhibits significantly enhanced OER activity, delivering a low overpotential of 215 mV at 100 mA cm-2 and maintaining long-term catalytic stability. Structural and compositional analyses reveal that Fe incorporation induces a distinct electronic modulation: Fe doping downshifts the d-band center, which weakens the adsorption of key OER intermediates such as *O and lowers the reaction energy barrier for the rate-determining step, thereby accelerating OER kinetics. Bader charge analysis and the crystal orbital Hamilton population further support weakened metal-oxygen bonding upon Fe substitution. The combined modulation of the local electronic structure and active site configuration provides clear mechanistic insight into the origin of the enhanced OER activity, presenting an effective design strategy for developing transition metal-based electrocatalysts with high OER performance.

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