Influence of the MnO2 Phase on Oxygen Evolution Reaction Performance for Low‐Loading Iridium Electrocatalysts.

Developing high‐performance, low‐loading, Ir‐based electrocatalysts for the oxygen evolution reaction (OER) in acidic media is still a great challenge. Herein, we fabricated an iridium manganese catalyst with only 5 % iridium. The influence of the manganese dioxide phase states (α‐, β‐, γ‐ and δ‐MnO2) on the OER performance of IrO2/MnO2 catalysts was investigated. α‐MnO2, as the substrate, can generate smaller iridium particles and more high‐valence‐state iridium to promote OER performance. Therefore, the 5 % IrO2/α‐MnO2 electrocatalyst exhibits excellent electrocatalytic OER performance with a high mass activity of 216.67 A/gIr and 655.33 A/gIr at 1.53 V in acidic and alkaline media, respectively, significantly outperforming commercial IrO2. [ABSTRACT FROM AUTHOR]