Engineering highly active oxygen sites in perovskite oxides for stable and efficient oxygen evolution

Perovskite oxides, represented by Ba0.5Sr0.5Co0.8Fe0.2O3-δ (BSCF), with O anion partially substituted by F anion are designed. Introduction of F in perovskite lattice initiated the transition of Co(III) and Fe(III) species to lower oxidation states and triggered the surface O anion to be activated to highly oxidative O2−/O‒, which is deemed to be efficient active sites for oxygen evolution reaction (OER) catalysis. As a consequence, the F...