Phase-Segregated SrCo_0.8Fe_0.5-O_3-δ/FeO Heterostructured Catalyst Promotes Alkaline Oxygen Evolution Reaction

Perovskite oxide is a promising alternative to noble metal electrocatalysts for the oxygen evolution reaction (OER). However, as one of the most active oxide catalysts, cubic SrCoO₃ presents poor OER performance relative to the theoretically predicted activity. Appropriate introduction of a guest component in the lattice and surface could largely promote the OER activity. Herein, we present a thermal-induced phase-segregation strategy to synthesize a heterostructured SrCo_0.8Fe_0.5-O_3-δ/FeO (SC8F5) catalyst for OER. This novel perovskite/Fe₃O₄ heterostructure allows us to enhance the electrical conductivity ability, increase the Co oxidation state, and activate the surface oxygen to active oxygen species (O₂^2-/O^-) for efficient OER. In contrast to the poor stability of SrCo_0.8Fe_0.2O_3-δ, we found that the SC8F5 heterostructure with segregated Fe₃O₄ on the surface can mitigate surface reconstruction and stabilize the catalyst structure, thereby increasing catalytic stability.