Breaking the Mutual‐Constraint of Bifunctional Oxygen Electrocatalysis via Direct O─O Coupling on High‐Valence Ir Single‐Atom on MnOx

Insufficient bifunctional activity of electrocatalysts for oxygen reduction reaction (ORR) and oxygen evolution reaction (OER) is the major obstruction to the application of rechargeable metal-air batteries. The primary reason is the mutual constraint of ORR and OER mechanism, involving the same oxygen-containing intermediates and demonstrating the scaling limitations of the adsorption energies. Herein, it is reported a high-valence Ir single atom anchored on manganese oxide (Ir_SA-MnO_x) bifunctional catalyst showing independent pathways for ORR and OER, i.e., associated 4e^- pathway on high-valence Ir site for ORR and a novel chemical-activated concerted mechanism for OER, where a distinct spontaneous chemical activation process triggers direct O─O coupling. The Ir_SA-MnO_x therefore delivers outstanding bifunctional activities with remarkably low potential difference (0.635 V) between OER potential at 10 mA cm^-2 and ORR half-wave potential in alkaline solution. This work breaks the scaling limitations and provides a new avenue to design efficient and multifunctional electrocatalysts.