Room-temperature ligancy engineering of perovskite electrocatalyst for enhanced electrochemical water oxidation

Perovskite oxides are significant candidates to develop electrochemical catalysts for water oxidation in consideration of their high catalysis capacity, low costing and excellent stability. Rational design of coordination structure and overcoming poor electronic transport are regarded as critical factors for outstanding perovskite-based oxygen evolution reaction (OER) catalysts. Herein, we report a mild chemical oxidation method to realize ligancy engineering from strongly-correlated brownmillerite Sr₂Co₂O₅ to perovskite phase Sr₂Co₂O₅₅, along with abundant oxygen vacancies formation and greatly boosted electric conductivity, which helps to form the active species of Co hydroxide/oxide on the surface of catalysts. The coupling effect of catalytic kinetics and unimpeded electronic movement brings high OER activities in Sr₂Co₂O₅₅with a low onset potential and a small Tafel slope. Our work not only displays in-depth understanding into the relationship among catalysis performance and multiple physical degrees of freedom, but also paves a new path to develop high-efficient electrochemical catalysts.