Bridging the Charge Accumulation and High Reaction Order for High‐Rate Oxygen Evolution and Long Stable Zn‐Air Batteries

Abstract Combining noble metals with nonnoble metals is an attractive strategy to balance the activity and cost of electrocatalysts. However, a guiding principle for selecting suitable nonnoble metals is still lacking. Herein, a thorough mechanistic study on the platform oxygen evolution reaction (OER) electrocatalyst of Ir@Co 3 O 4 to deeply understand the synergy between Ir and Co 3 O 4 for the boosted OER has been carried out. It is demonstrated that the pseudocapacitive feature of Co 3 O 4 plays a key role in accumulating sufficient positive charge [ Q ], while the Ir sites are responsible for achieving a high reaction order (β), synergistically contributing to the high OER activity of Ir@Co 3 O 4 through the rate law equation. Specifically, Ir@Co 3 O 4 displays a low overpotential of 280 mV at 10 mA cm −2 with a small Ir loading of 1.4 wt%. Ir@Co 3 O 4 is further applied to Zn‐air batteries, which enables a low charging potential and thus alleviates the oxidative corrosion of the air electrode, leading to improved cycle stability of 210 h at 20 mA cm −2 . This work demonstrates that anchoring active noble metal sites (for high β) on pseudocapacitive supports (for high [ Q ]) is highly favorable to the OER process, providing a clear guidance for boosting the utilization of noble metals in electrocatalysis.