Plasma‐Induced Oxygen Defect Engineering in Perovskite Oxide for Boosting Oxygen Evolution Reaction

Abstract Perovskite oxides are considered highly promising candidates for oxygen evolution reaction (OER) catalysts due to their low cost and adaptable electronic structure. However, modulating the electronic structure of catalysts without altering their nanomorphology is crucial for understanding the structure‐property relationship. In this study, a simple plasma bombardment strategy is developed to optimize the catalytic activity of perovskite oxides. Experimental characterization of plasma‐treated LaCo 0.9 Fe 0.1 O 3 (P‐LCFO) reveals abundant oxygen vacancies, which expose numerous active sites. Additionally, X‐ray photoelectron spectroscopy and X‐ray absorption fine structure analyses indicate a low Co valence state in P‐LCFO, likely due to the presence of these oxygen vacancies, which contributes to an optimized electronic structure that enhances OER performance. Consequently, P‐LCFO exhibits significantly improved OER catalytic activity, with a low overpotential of 294 mV at a current density of 10 mA cm −2 , outperforming commercial RuO 2 . This work underscores the benefits of plasma engineering for studying structure‐property relationships and developing highly active perovskite oxide catalysts for water splitting.