Lanthanum-Induced MnO₂/Mn₂O₃ Dual-Phase Heterostructure for Efficient and Stable Acidic Oxygen Evolution

Area of Science:

• Materials Science
• Electrochemistry
• Catalysis

Background:

• Nonprecious metal electrocatalysts are crucial for commercializing proton exchange membrane water electrolyzers.
• Manganese oxides show promise but suffer from an activity-stability trade-off in acidic media due to Mn3+ solubility.

Purpose of the Study:

• To develop a low-cost, highly active, and durable nonprecious metal electrocatalyst for the oxygen evolution reaction (OER) in acidic media.
• To overcome the activity-stability limitations of manganese-based oxides.

Main Methods:

• A simple one-step heating strategy was employed to synthesize lanthanum (La)-doped MnO2/Mn2O3 on carbon cloth.
• The strategy involved introducing La3+ ions to induce lattice distortion, charge compensation, and oxygen vacancies.

Main Results:

• The La-doped MnOx catalyst exhibited significantly enhanced OER activity, with an overpotential of 294 mV at 10 mA/cm2.
• The catalyst demonstrated remarkable stability, maintaining performance for over 110 hours in 0.5 M H2SO4.
• In situ hydroxylation and passivation layer formation protected the catalyst framework from acid corrosion.

Conclusions:

• Lanthanum doping is an effective strategy to improve the performance and durability of manganese-based OER electrocatalysts in acidic environments.
• The developed catalyst represents a significant advancement for proton exchange membrane water electrolyzer technology.
• This study introduces a novel rare-earth-element-inducing approach for designing high-performance electrocatalysts.