Boosting the Electrocatalytic Oxygen Evolution of Perovskite LaCo 1- x Fe x O 3 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- x Fe x O 3 with yolk-shell nanostructures is developed. Benefiting from the unique structural and compositional merits, LaCo 0.75 Fe 0.25 O 3 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 LaCoO 3 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 0.75 Fe 0.25 O 3 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.