Strain-Driven Surface Reconstruction During the Alkaline Oxygen Evolution Reaction: a Model Thin-Film Study.

Area of Science:

• Materials Science
• Electrochemistry
• Catalysis

Background:

• Dynamic surface reconstruction is crucial for oxide electrocatalyst performance in the oxygen evolution reaction (OER).
• Controlling this reconstruction under operating conditions is a significant challenge in catalyst design.

Purpose of the Study:

• To investigate how lattice strain influences surface reconstruction in perovskite oxides.
• To establish metal-oxygen bond length as a tunable parameter for optimizing electrocatalyst activity.

Main Methods:

• Epitaxial growth of LaNiO3 (LNO) thin films to create controlled lattice strain.
• Characterization of Ni redox behavior and surface reconstruction under varying strain conditions.
• Testing catalyst performance in alkaline electrolytes for the oxygen evolution reaction.

Main Results:

• Tensile strain enhances Ni reducibility and promotes surface reconstruction, increasing it by an order of magnitude compared to compressive strain.
• Tensile-strained LNO showed a 5.7-fold activity enhancement in Fe-containing electrolytes due to synergistic Fe interactions.
• Scandium doping in powder catalysts mimicked strain effects, inducing similar reconstruction and activity.

Conclusions:

• Lattice strain effectively modulates Ni redox behavior and surface reconstruction in perovskite oxides.
• Metal-oxygen bond length is a viable design parameter for tuning electrocatalyst surface dynamics and performance.
• The demonstrated approach is scalable from thin films to powder catalysts for OER applications.