Rare earth single atoms enhance manganese oxide's electrochemical oxygen evolution

An international group of researchers has developed a novel approach that enhances the efficiency of the oxygen evolution reaction (OER), a key process in renewable energy technologies. By introducing rare earth single atoms into manganese oxide (MnO₂), the group successfully modulated oxygen electronic states, leading to unprecedented improvements in OER performance.

Their findings were published in the journal Nano Energy on June 10, 2024.

Transition-metal-based oxides have been widely explored for their potential as active OER catalysts. However, the capacity of these catalysts is hindered by the adsorbate evolution mechanism, which limits the effective release of oxygen (O₂) during the reaction.

"We constructed localized asymmetric gadolinium-oxygen-manganese units on MnO₂, which helps accumulate electrons at oxygen sites," notes Hao Li, corresponding author of the paper and an associate professor at the Advanced Institute for Materials Research (WPI-AIMR) at Tohoku University. "By doing this, the catalysts achieve a lower overpotential and maintain stability over time, making it a suitable alternative to traditional catalysts such as ruthenium dioxide (RuO₂)."

Hao Li and his colleagues employed an argon plasma-assisted strategy to introduce rare earth elements on the catalyst surface. In this strategy, argon gas is ionized, energizing and helping break the argon atoms into ions and electrons, thereby making it easier to interact with and modify materials.

"We have addressed the challenges associated with the adsorbate evolution mechanism that limits the performance of transition-metal-based oxides like MnO₂," adds Di Zhang, co-author of the study and a Specially Appointed Assistant Professor at WPI-AIMR. "By improving the understanding of the structure-activity relationship under the lattice oxygen mechanism, the research provides a foundation for more effective catalyst design."

Building on the success of this study, the group plans to extend their methodology to a variety of electrochemical reactions. This approach will help further decipher unique structure-activity correlations, ultimately contributing to the design of even more effective and high-performance electrocatalysts.