Lanthanum-Induced Gradient Fields in Asymmetric Heterointerface Catalysts for Enhanced Oxygen Electrocatalysis

Area of Science:

• Materials Science
• Electrochemistry
• Catalysis

Background:

• Metal-nitrogen-carbon (M-N-C) catalysts are promising alternatives to noble metals for oxygen electrocatalysis.
• Challenges include disordered active sites and poor durability due to atomic migration during synthesis.

Purpose of the Study:

• To develop a strategy for directional control of atomic migration in M-N-C catalysts.
• To engineer a stable, high-performance heterointerface catalyst for enhanced oxygen electrocatalysis.

Main Methods:

• Incorporation of a foreign metal (La) to exploit the Kirkendall effect for directional atomic diffusion.
• Fabrication of an asymmetric multiphase heterointerface catalyst (LaN/LaFe-NC).

Main Results:

• Achieved directional control of atomic diffusion, creating well-defined, asymmetric active sites.
• The LaN/LaFe-NC catalyst exhibited enhanced interfacial charge transport and improved intrinsic activity and stability.
• Demonstrated superior performance in a rechargeable Zn-air battery with high power density (211 mW cm⁻²) and long cycling stability (>240 h).

Conclusions:

• Established a generalizable atomic-level design strategy for robust heterointerface catalysts.
• The findings offer valuable insights for advancing renewable energy conversion and storage systems.