Surface Structure Modulation of La_0.6Sr_0.4CoO₃ Films on SrTiO₃ (001) Substrate under Electrochemical Conditions

Area of Science:

• Materials Science
• Surface Chemistry
• Catalysis

Background:

• Lanthanum strontium cobaltite (La_0.6Sr_0.4CoO₃) is a key material for water-splitting catalysis.
• Understanding surface structure evolution is crucial for optimizing catalyst performance.

Purpose of the Study:

• To investigate the surface structural changes of La_0.6Sr_0.4CoO₃ under electrochemical conditions.
• To correlate surface structure modulation with catalytic activity in water splitting.

Main Methods:

• Surface X-ray diffraction (SXRD) was employed to analyze the film's structure.
• Experiments were conducted under both vacuum and electrochemical conditions.

Main Results:

• The pristine La_0.6Sr_0.4CoO₃ surface featured a polarized SrCoO₃ layer and a CoO₂ termination.
• Electrochemical treatment induced an additional CoO₆ double layer, reducing surface polarization.
• Structural changes correlated with increased electrode current, indicating enhanced catalytic activity.

Conclusions:

• The surface structure of La_0.6Sr_0.4CoO₃ is dynamically modulated by electrochemical potential.
• This reversible structural modulation is linked to atomic displacements and changes in cobalt's ionic radius.
• Surface structure engineering offers a pathway to enhance water-splitting catalyst performance.