Activity-stability relationship in the surface electrochemistry of the oxygen evolution reaction

Area of Science:

• Electrochemistry
• Materials Science
• Catalysis

Background:

• A stable hydrogen economy relies on efficient oxygen evolution reaction (OER) catalysts.
• Understanding the interplay between oxide material stability and reactivity is crucial for OER advancement.

Purpose of the Study:

• To investigate the functional relationship between stability and reactivity of ruthenium oxide surfaces during OER.
• To elucidate the role of surface chemistry and defect sites in OER kinetics and material degradation.

Main Methods:

• Surface chemistry analysis of monometallic ruthenium oxide in acidic and alkaline media.
• Investigation of polycrystalline and single-crystalline SrRuO(3) thin films in alkaline solutions.
• Correlation of OER kinetics with material stability and ruthenium ion valence state.

Main Results:

• OER kinetics are predominantly controlled by the stability of ruthenium surface atoms.
• A similar activity-stability relationship was observed for SrRuO(3) thin films.
• Ruthenium ion dissolution, triggered by valence state changes (Ru(4+) to Ru(n>4+)), creates active defect sites during OER.

Conclusions:

• Complete oxide stability leads to inactivity for the OER.
• Optimal OER materials must achieve a balance between stability and activity to manage the dissolution rate.
• Careful control of ruthenium oxide dissolution is essential for efficient and durable OER catalysis.