Ceria‐Optimized Oxygen‐Species Exchange in Hierarchical Bimetallic Hydroxide for Electrocatalytic Water Oxidation

Abstract The utilization of rare earth elements to regulate the interaction between catalysts and oxygen‐containing species holds promising prospects in the field of oxygen electrocatalysis. Through structural engineering and adsorption regulation, it is possible to achieve high‐performance catalytic sites with a broken activity‐stability tradeoff. Herein, this work fabricates a hierarchical CeO 2 /NiCo hydroxide for electrocatalytic oxygen evolution reaction (OER). This material exhibits superior overpotentials and enhanced stability. Multiple potential‐dependent experiments reveal that CeO 2 promotes oxygen‐species exchange, especially OH − ions, between catalyst and environment, thereby optimizing the redox transformation of hydroxide and the adsorption of oxygen‐containing intermediates during OER. This is attributed to the reduction in the adsorption energy barrier of Ni to *OH facilitated by CeO 2 , particularly the near‐interfacial Ni sites. The less‐damaging adsorbate evolution mechanism and the CeO 2 hierarchical shell significantly enhance the structural robustness, leading to exceptional stability. Additionally, the observed “self‐healing” phenomenon provides further substantiation for the accelerated oxygen exchange. This work provides a neat strategy for the synthesis of ceria‐based complex hollow electrocatalysts, as well as an in‐depth insight into the co‐catalytic role of CeO 2 in terms of oxygen transfer.