Synergistic Interplay between Fe-Based Perovskite Oxides and Co in Electrolyte for Efficient Oxygen Evolution...

Area of Science:

• Materials Science
• Electrochemistry
• Catalysis

Background:

• Perovskite oxides are key electrocatalysts for the oxygen evolution reaction (OER) in alkaline media.
• The influence of electrolyte transition metal ions, beyond iron, on OER activity is not well understood.
• Investigating electrolyte Co ion effects on Fe-based perovskites is crucial for advancing OER catalysis.

Purpose of the Study:

• To compare the impact of electrolyte Co ions on the OER activity of two Fe-based perovskite oxides: Ba$_{0.5}$Sr$_{0.5}$FeO$_{3-δ}$ and LaFeO$_{3}$.
• To elucidate the surface structural changes and Co ion incorporation mechanisms during OER.

Main Methods:

• Electrochemical testing of Ba$_{0.5}$Sr$_{0.5}$FeO$_{3-δ}$ and LaFeO$_{3}$ in Co-containing and Co-free electrolytes.
• Surface analysis techniques to investigate structural transformations and elemental incorporation after OER cycling.

Main Results:

• Ba$_{0.5}$Sr$_{0.5}$FeO$_{3-δ}$ OER activity significantly increased with electrolyte Co ions, forming an amorphous surface layer with incorporated Co.
• LaFeO$_{3}$ showed minimal OER activity change with electrolyte Co ions, despite Co detection on its unchanged crystalline surface.
• Synergistic effects between perovskite surface transformation and electrolyte Co ions enhance OER activity.

Conclusions:

• Electrolyte Co ions can significantly enhance OER activity for specific perovskite oxides like Ba$_{0.5}$Sr$_{0.5}$FeO$_{3-δ}$ through surface restructuring.
• The interplay between perovskite structural changes and electrolyte metal ions is critical for optimizing OER electrocatalysts.
• This study provides insights into designing advanced perovskite electrocatalysts by controlling electrolyte composition.