Surface-Engineered Manganese Oxide via Sodium Borohydride for Optimized ORR Active Electrocatalyst.

Area of Science:

• Materials Science
• Electrochemistry
• Catalysis

Background:

• Manganese oxide octahedral molecular sieves (OMS) are cost-effective and durable electrocatalysts for oxygen reduction reactions (ORRs).
• Their application is hindered by low electrical conductivity and insufficient intrinsic activity.

Purpose of the Study:

• To enhance the ORR performance of OMS materials.
• To address limitations of low conductivity and activity through surface modification.

Main Methods:

• Surface reduction etching treatment using sodium borohydride (NaBH₄).
• Optimization of oxygen vacancies and Mn³⁺/Mn⁴⁺ ratio on OMS surfaces.

Main Results:

• A 6 mmol/L NaBH₄ treatment significantly increased surface oxygen vacancies, enhancing ORR active sites.
• The treatment optimized the Mn³⁺/Mn⁴⁺ ratio, improving electron transfer.
• The optimized OMS achieved a half-wave potential of 0.661 V.

Conclusions:

• Surface reduction etching is a viable and scalable method to improve OMS electrocatalysts.
• Optimized OMS shows potential as a platinum-free alternative for ORR in energy technologies.