Interweaving Two‐Dimensional Co‐Corrole‐Based Covalent Organic Framework for Significantly Improved Electrocatalytic Oxygen Reduction Reaction

ABSTRACT

Two‐dimensional (2D) covalent organic frameworks (COFs) are promising electrocatalysts but suffer from limited active‐site accessibility, sluggish mass transportation in narrow‐spaced interlayers, and interlayer sliding during catalysis. Herein, we report the synthesis of Co‐corrole‐based 2D COF 1 and its interlayer‐interweaved derivatives 2 and 3 for electrocatalytic oxygen reduction reaction (ORR). The reaction of Co tris(4‐formylphenyl)corrole and 1,4‐phenylenediamine gave 2D COF 1 with an interlayer spacing of 4.2 Å. Using pyrazine and bipyridine as bidentate molecular pillars to interweave 2D layers of 1 via bridging interlayer Co corroles, we obtained COFs 2 and 3 with interlayer spacing of 6.4 and 10.3 Å, respectively. Structural and spectroscopic analyses confirmed that the expanded interlayer spacing is caused by the axial Co–N coordination between Co corroles and bidentate molecular pillars. Compared to 1 , COFs 2 and 3 exhibited markedly enhanced 4H ⁺ /4e ^– ORR activity and durability, with half‐wave potential increased from 0.80 to 0.89 V and 0.94 V versus RHE. Rotation‐rate‐dependent Tafel measurements revealed improved mass transportation in the enlarged interlayer spaces in 2 and 3 . The Zn‐air battery using COF 3 delivered a high open‐circuit voltage of 1.52 V and a large peak power density of 193.5 Mw cm ⁻² , outperforming Pt/Ru benchmarks.