A Doping‐Induced SrCo_0.4Fe_0.6O₃/CoFe₂O₄ Nanocomposite for Efficient Oxygen Evolution in Alkaline Media

Abstract

Perovskite and spinel oxides are promising alternatives to noble metal‐based electrocatalysts for oxygen evolution reaction (OER). Herein, a novel perovskite/spinel nanocomposite comprised of SrCo_0.4Fe_0.6O₃ and CoFe₂O₄ (SCF/CF) is prepared through a simple one‐step method that incorporates iron doping into a SrCoO_3‐δ matrix, circumventing complex fabrication processes typical of these materials. At a Fe dopant content of 60%, the CoFe₂O₄ spinel phase is directly precipitated from the parent SrCo_0.4Fe_0.6O₃ perovskite phase and the number of active B‐site metals (Co/Fe) in the parent SCF can be maximized. This nanocomposite exhibits a remarkable OER activity in alkaline media with a small overpotentional of 294 mV at 10 mA cm⁻². According to surface states analysis, the parent SCF perovskite remains in its pristine form under alkaline OER conditions, serving as a stable substrate, while the second spinel CF is covered by 5/8 monolayer (ML) O*, exhibiting considerable affinity toward the oxygen species involved in the OER. Analysis based on advanced OER microkinetic volcano model indicates that a 5/8 ML O* covered‐CF is the origin for the remarkable activity of this nanocomposite. The results reported here significantly advance knowledge in OER and can boost application, scale‐up and commercialisation of electrocatalytic technologies toward clean energy devices.