Cationic Defect Engineering in Perovskite La₂CoMnO₆ for Enhanced Electrocatalytic Oxygen Evolution.

Area of Science:

• Materials Science
• Electrochemistry
• Catalysis

Background:

• Sustainable energy conversion demands highly efficient electrocatalysts for reactions like the oxygen evolution reaction (OER).
• Metal oxides often suffer from low electrical conductivity and limited active sites, hindering their catalytic efficiency.
• Defect engineering presents a viable strategy to overcome these limitations in electrocatalyst development.

Purpose of the Study:

• To investigate the impact of oxygen defects on the OER performance of La2CoMnO6-δ perovskite oxides.
• To explore the A-site cation defect strategy for introducing and controlling oxygen vacancies.
• To develop improved electrocatalysts for sustainable energy applications.

Main Methods:

• Synthesis of La2CoMnO6-δ perovskite oxides with varying A-site cation content to introduce oxygen defects.
• Characterization of the introduced oxygen defects and their correlation with electrochemical properties.
• Electrochemical evaluation of the catalysts for oxygen evolution reaction (OER) performance, including overpotential measurements.

Main Results:

• Defective La1.8CoMnO6-δ (L1.8CMO) catalyst demonstrated significantly enhanced OER activity.
• An overpotential of 350 mV at 10 mA cm-2 was achieved, representing a 120 mV improvement over the pristine perovskite.
• Increased surface oxygen vacancies, optimized B-site transition metal e_g occupation, and larger surface area contributed to the enhanced performance.

Conclusions:

• A-site cation defect engineering is an effective strategy for creating oxygen defects in perovskite oxides.
• The resulting defect-mediated perovskites exhibit superior electrocatalytic activity for the oxygen evolution reaction.
• This approach holds potential for designing advanced electrocatalysts for clean energy technologies.