Tailoring Multiple Coordination Environments of Cobalt‐Only Ladder Organic Framework for Bifunctional Oxygen Electrocatalysis

Abstract Developing efficient oxygen electrocatalysts is crucial for the progress of future energy conversion and storage systems. Herein, a fully conjugated ladder organic framework is designed with densely populated cobalt sites (HATN‐BiSalphen@KB). The molecular characteristics of the catalytic sites provide a trustworthy model for investigating the oxygen catalysis mechanism. Theoretical calculations combined with in situ ATR‐FTIR spectroscopy demonstrate that the electronic interaction of the Co 2 N 4 O 2 and CoN 2 Cl 2 sites shifts the d ‐band center of Co atoms, optimizing oxygen intermediate adsorption/desorption energetics and boosting bifunctional catalytic performance. Consequently, the catalyst exhibits exceptional bifunctional activity, achieving a remarkable oxygen reduction reaction (ORR) half‐wave potential of 0.983 V alongside a low oxygen evolution reaction (OER) overpotential of 310 mV at 10 mA cm −2 . In addition, the assembled rechargeable zinc‐air batteries demonstrate a high peak power density of 254.1 mW cm −2 and outstanding charge–discharge cycling stability for 450 h. This work provides valuable insights into designing advanced bifunctional oxygen electrocatalysts through atomic‐level modulation of the coordination environment.