Boosting the Electrocatalytic Oxygen Evolution of Perovskite LaCo_1−xFe_xO₃ by the Construction of Yolk-Shell Nanostructures and Electronic Modulation

Realizing the rational design of perovskite oxides with controllable compositions and nanostructures remains a tremendous challenge for the development of efficient electrocatalysts. Herein, a ligand-assisted synthetic strategy to fabricate perovskite oxides LaCo_1−xFe_xO₃ with yolk-shell nanostructures is developed. Benefiting from the unique structural and compositional merits, LaCo_0.75Fe_0.25O₃ exhibits an overpotential of 310 mV at a current density of 10 mA cm⁻² and long-term stability of 100 h for the oxygen evolution reaction. In situ Raman spectroscopy demonstrates that Fe substitution facilitates the pre-oxidation of Co sites and induces the surface reconstruction into active Co oxyhydroxides at a relatively lower applied potential, guaranteeing excellent catalytic performances. Density functional theory calculations unravel that the appropriate introduction of Fe into perovskite LaCoO₃ leads to the improved electroactivity and durability of the catalyst for the oxygen evolution reaction (OER). Fe-3d orbitals show a pinning effect on Co-3d orbitals to maintain the stable valence state of Co sites at the low overpotential of the OER. Furthermore, Zn–air batteries (ZABs) assembled with LaCo_0.75Fe_0.25O₃ display a high open circuit potential of 1.47 V, superior energy density of 905 Wh kg⁻¹ _Zn, and excellent stability in a large temperature range. This work supplies novel insights into the future developments of perovskite-based electrocatalysts. © 2022 Wiley-VCH GmbH.