Cu‐Induced Structural Transformation and Electronic Modulation of Co(OH) ₂ Enabling Stable and Efficient Oxygen Evolution Reaction

Abstract Transition metal‐based catalysts typically undergo oxidative reconstruction to form active phases during oxygen evolution reaction (OER), but continuous reconstruction may trigger dissolution of active phases and catalyst deactivation. Synergistically optimizing reconstruction kinetics and structural stability is a key challenge in enhancing practicality of such catalysts. Here, a dynamic self‐reconstruction regulation strategy is proposed, driven by selective Cu leaching, to synthesize CuCo layered double hydroxide (CuCo LDH) pre‐catalyst, where Cu species with low redox potential are preferentially and selectively leached, inducing controllable deep reconstruction. Combined in situ characterizations and theoretical calculations reveal the dual regulatory mechanism of Cu species: its selective preferential leaching induces the formation of CoOOH active phase, while stabilizes the Co oxidation state via electronic interactions, suppressing the over‐oxidation. The reconstructed Act‐CuCo LDH forms crystalline‐amorphous heterostructure, which upshifts the d‐band center and optimizes oxygen intermediates adsorption. As expected, Act‐CuCo LDH exhibits outstanding activity and only 18 mV decay for 550 h stability test at 200 mA cm −2 . Additionally, the anion exchange membrane electrolyzer using Act‐CuCo LDH || Pt/C remains stable for 200 h at 1.0 A cm −2 . This study achieves a balance between deep reconstruction and structural stability, providing a design strategy for highly efficient and stable OER catalysts.