Engineering Surface Reconstruction of Perovskite Oxides through Vanadium Doping and Alkalinity Regulation for Enhanced Oxygen Evolution

Lattice oxygen participation in perovskite electrocatalysts can significantly enhance oxygen evolution reaction (OER) activity, yet it often compromises long-term durability due to severe surface reconstruction and bulk degradation. Here, we deliberately engineer surface reconstruction to reconcile activity and stability by preconstructing a highly active and robust (oxy)hydroxide layer on a perovskite oxide. A vanadium-doped perovskite, SrFe0.25Co0.25Ni0.18V0.02Mo0.3O3 (SFCNM-V0.02), is rationally designed, in which V-doping facilitates rapid OH–-induced reconstruction. Preimmersion in concentrated KOH accelerates the formation of a dense and stable amorphous (oxy)hydroxide layer that suppresses bulk dissolution while serving as the dominant catalytic active phase. Consequently, SFCNM-V0.02 delivers a low overpotential of 265 mV at 10 mA cm–2 and exceptional operational stability exceeding 1100 h in 1 M KOH. Furthermore, by correlating the degree of surface reconstruction with catalytic activity, we analyzed the origin of the pH-dependent variation observed in this work, which provides useful implications for appropriately evaluating pH-dependent behaviors in electrocatalysis. This work demonstrates that controlled surface reconstruction fundamentally governs OER performance in perovskite oxides and provides practical design principles for durable, high-efficiency OER electrocatalysts.