Manipulating Heterogeneous Surface/Interface Reconstruction of Nickel Molybdate Nanofiber by In Situ Prussian Blue Analogs Etching Strategy for Oxygen Evolution

Abstract

Bimetallic oxides are promising electrocatalysts due to their rich composition, facile synthesis, and favorable stability under oxidizing conditions. This paper innovatively proposes a strategy aimed at constructing a one-dimensional heterostructure (Fe–NiO/NiMoO₄ nanoparticles/nanofibers). The strategy commences with the meticulous treatment of NiMoO₄ nanofibers, utilizing in situ etching techniques to induce the formation of Prussian Blue Analog compounds. In this process, [Fe(CN)₆]³⁻ anions react with the NiMoO₄ host layer to form a steady NiFe PBA. Subsequently, the surface/interface reconstituted NiMoO₄ nanofibers undergo direct oxidation, leading to a reconfiguration of the surface structure and the formation of a unique Fe–NiO/NiMoO₄ one-dimensional heterostructure. The catalyst showed markedly enhanced electrocatalytic performance for the oxygen evolution reaction. Density functional theory results reveal that the incorporation of Fe as a dopant dramatically reduces the Gibbs free energy associated with the rate-determining step in the oxygen evolution reaction pathway. This pivotal transformation directly lowers the activation energy barrier, thereby significantly enhancing electron transfer efficiency.