Switchable wetting of oxygen-evolving oxide catalysts

Area of Science:

• Electrochemistry
• Materials Science
• Surface Chemistry

Background:

• Catalyst surface wettability is crucial for performance.
• Controlling wettability often involves surface treatments.
• Understanding solid-liquid interfaces is key for catalysis.

Purpose of the Study:

• To investigate potential-regulated hydrophobicity/hydrophilicity at cobalt-based oxide interfaces.
• To link switchable wetting behavior to catalytic activity and stability for the oxygen evolution reaction.
• To provide fundamental insights into solid-liquid interfacial interactions.

Main Methods:

• Electrochemical liquid-phase transmission electron microscopy (EP-TEM) for real-time observation.
• Operando electron energy-loss spectroscopy (EELS) for chemical analysis.
• Analysis of liquid movement and interfacial capacitance changes.

Main Results:

• Switchable wetting observed at cobalt-based oxide interfaces in alkaline solution.
• Distinct wettability behaviors correlated with specific electrochemical potential ranges.
• Low potentials reduced hydrophobicity; high potentials showed thinner liquid layers during oxygen evolution.
• Reversible surface reconstruction to oxyhydroxide phase altered interfacial capacitance.

Conclusions:

• Direct link established between physical wetting and chemical oxygen evolution reaction (OER) on single particles.
• Potential-driven electrowetting influences catalyst activity and stability.
• Fundamental insights into solid-liquid interfacial interactions for oxygen-evolving oxides are provided.