Anion Intercalation Engineering in High‐Entropy LDHs for Kinetically Boosted Dual‐Pathway Oxygen Evolution

ABSTRACT The oxygen evolution reaction (OER) mechanism on layered double hydroxides (LDHs) involves a delicate balance between the adsorbate evolution mechanism (AEM) and the lattice oxygen mechanism (LOM), with intercalated anions serving as a critical yet underexplored regulatory factor. Herein, four different anions (CO ₃ ²⁻ , VO ₄ ³⁻ , WO ₄ ²⁻ , MoO ₄ ²⁻ ) are intercalated into high‐entropy LDHs to systematically investigate their structure‐dependent effects. The results demonstrate that intercalated anion engineering governs the electronic structure of Ru active sites and concurrently promotes lattice oxygen participation in the OER. Although all anions promote a mixed AEM/LOM pathway, MoO ₄ ²⁻ induces the most pronounced electronic modification, lowering the Ru oxidation state and upshifting its d‐band center. This electronic configuration reduces the reaction energy barrier, thereby optimizing the AEM pathway, while simultaneously enabling moderate activation of lattice oxygen to facilitate the LOM route. As a result, the HE–MoO ₄ ²⁻ –LDH catalyst exhibits outstanding OER performance, achieving a low overpotential of 229.5 mV at 10 mA cm ⁻² with excellent operational stability. This work provides a key design guideline for tailoring reaction pathways in high‐entropy electrocatalysts through anion intercalation.