Extremely Active and Robust Ir‐Mn Dual‐Atom Electrocatalyst for Oxygen Evolution Reaction by Oxygen‐Oxygen Radical Coupling Mechanism

A novel Ir‐Mn dual‐atom electrocatalyst is synthesized by a facile ion‐exchange method by incorporating Ir in SrMnO3, which yields an extremely high activity and stability for the oxygen evolution reaction (OER). The ion exchange process occurs in a self‐limitation way, which favors the formation of Ir‐Mn dual‐atom in the IrMnO9 unit. The incorporation of Ir modulates the electronic structure of both Ir and Mn, thereby resulting in a shorter distance of the Ir‐Mn dual‐atom (2.41 Å) than the Mn‐Mn dual‐atom (2.49 Å). The modulated Ir‐Mn dual‐atom enables the same spin direction O (↑) of the adsorbed *O intermediates, thus facilitating the direct coupling of the two adsorbed *O intermediates to release O2 via the oxygen‐oxygen radical coupling mechanism. Electrochemical tests reveal that the Ir‐SrMnO3 exhibits a superior OER's activity with a low overpotential of 207 mV at 10 mA cm‐2 and achieves a mass specific activity of 1100 A gIr‐1 at 1.5 V. The proton‐exchange‐membrane water electrolyzer with the Ir‐SrMnO3 catalyst exhibits a low electrolysis voltage of 1.63 V at 1.0 A cm‐2 and a stable 2000‐h operation with a decay of only 15 μV h‐1 at 0.5 A cm‐2.