Vector substrate design for grain boundary engineering: boosting oxygen evolution reaction performance in LaNiO₃

Area of Science:

• Materials Science
• Catalysis
• Surface Chemistry

Background:

• Grain boundaries (GBs) in materials offer unique electronic and structural properties.
• GBs are promising for developing advanced catalysts for various reactions, including oxygen evolution.
• Controlling GB quantity in catalysts is crucial but challenging for identifying functional attributes.

Purpose of the Study:

• To engineer specific grain boundaries (GBs) in LaNiO3 (LNO) using a vector substrate design.
• To evaluate the performance of engineered LNO GBs in the oxygen evolution reaction (OER).
• To understand the relationship between GB structure, surface reconstruction, and OER activity.

Main Methods:

• Engineered specific GBs: (001)/(110), (001)/(111), and (110)/(111) in LaNiO3.
• Utilized a vector substrate design approach for GB engineering.
• Evaluated OER performance and surface reconstruction of engineered LNO GBs.

Main Results:

• The LNO (110)/(111) GB demonstrated the fastest surface reconstruction to Ni oxyhydroxide.
• This GB exhibited superior OER performance, achieving 2.36 mA cm-2 at an overpotential of 400 mV.
• Enhanced performance is linked to stronger Ni-O covalency and optimal O 2p-band center position.

Conclusions:

• Engineered GBs in LNO can significantly enhance OER performance.
• The (110)/(111) GB in LNO is a highly effective catalyst for OER due to its electronic properties and reconstruction behavior.
• This study provides insights into optimizing catalysts by controlling grain boundary structures.