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

TL;DR

Researchers improved manganese oxide's performance as an electrocatalyst for oxygen reduction reactions by creating more active sites and enhancing electron transfer.

Contribution

A surface reduction etching method using NaBH4 is introduced to enhance OMS electrocatalytic activity for ORR.

Findings

Surface treatment with NaBH4 increased oxygen vacancies, improving ORR activity.

The optimized material showed a half-wave potential of 0.661 V, rivaling platinum catalysts.

The method effectively adjusted the Mn3+/Mn4+ ratio, enhancing electron transfer during ORR.

Abstract

Manganese oxide octahedral
molecular sieves (OMS) have garnered
attention as promising electrocatalysts for oxygen reduction reactions
(ORRs) due to their cost-effectiveness as well as durability. However,
their practical application is limited by inherent drawbacks such
as low electrical conductivity and insufficient intrinsic catalytic
activity. To overcome these challenges, we employed a surface reduction
etching treatment using NaBH4 to optimize the oxygen vacancy
of OMS. The treatment with a 6 mmol/L NaBH4 solution significantly
increased the number of oxygen vacancies on the surface of OMS, which
serve as crucial active sites facilitating the adsorption and dissociation
of oxygen molecules, thereby enhancing ORR activity. Furthermore,
the treatment effectively regulated the Mn3+/Mn4+ ratio on the nanosphere surface, further promoting catalytic efficiency
by facilitating the transfer of electrons during the ORR process.
Notably, the optimized OMS material exhibited a remarkable half-wave
potential of 0.661 V, highlighting its improved performance and potential
as a suitable replacement for traditional platinum-based catalysts.
This straightforward and scalable method unlocks the potential of
OMS materials for practical applications, offering a promising solution
for energy storage as well as conversion technologies that require
efficient ORR catalysts.

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