Exceptionally Robust Face-Sharing Motifs Enable Efficient and Durable Water Oxidation.

Area of Science:

• Materials Science
• Electrochemistry
• Catalysis

Background:

• Corner-sharing oxides often undergo structural reconstruction during oxygen-evolution reactions (OER), limiting their stability and efficiency in water electrolysis.
• Developing alternative structures with dynamically stable active sites is crucial for advancing sustainable energy technologies.

Purpose of the Study:

• To identify and characterize a novel oxide material with enhanced stability and activity for alkaline OER.
• To investigate the structural and electronic properties contributing to the material's performance in water electrolysis.

Main Methods:

• Synthesis and characterization of a 1D 5H-polytype Ba5Bi0.25Co3.75FeO14-δ oxide with face-sharing motifs.
• Operando spectroscopy to assess structural stability under OER conditions.
• Electrochemical measurements to determine OER activity and overpotential.
• Computational studies to understand the reaction mechanism and electronic properties.

Main Results:

• The face-sharing Ba5Bi0.25Co3.75FeO14-δ oxide demonstrated exceptional stability, maintaining its structure over 110 hours of OER operation with negligible degradation.
• Achieved a low overpotential of 308 mV at 10 mA cm⁻² in 0.1 M KOH, attributed to higher Co valence and a smaller orbital bandgap enhancing electron transport.
• Mechanism studies revealed accelerated deprotonation via a steric inductive effect, promoting lattice-oxygen participation in the OER.

Conclusions:

• The discovered 1D face-sharing oxide offers a promising alternative to conventional corner-sharing materials for efficient and stable alkaline OER.
• This work establishes a rational design strategy for creating dynamic, stable, and active sites for sustainable energy applications, particularly water electrolysis.