Construction of\na Pore-Confined Catalyst in a Vinylene-Linked\nCovalent Organic Framework for the Oxygen Reduction Reaction

Two-dimensional metal-containing covalent organic frameworks\n(COFs)\nhave been employed as electrocatalysts. However, the metal sites were\nstacked within the layers with strong interactions, which hindered\nmass transport to them in the catalytic process. Herein, we constructed\na pore-confined catalyst in a vinylene-linked COF for the oxygen reduction\nreaction (ORR) via the Katritzky reaction. By anchoring the catalytic\nsites along the pore walls with covalent bonds, the catalytic units\nwere well-exposed during the catalytic process and retained crystallinity\nand porosity, facilitating mass access to the metal sites. In addition,\nthe electron/charge transported from the framework to the metal units\nmodulated the electronic states, thus improving the catalytic activity.\nThe catalytic COF exhibited a half-wave potential of 0.85 V and a\nmass activity of 109.7 A g<sup>–1</sup>, which are better than\nthose of other reported COFs. Theoretical calculations revealed that\nthe interaction between the framework and metal sites contributed\nto the easy formation of OOH* and OH*, resulting in high activity.\nThis work provides insights into designing catalytic COFs based on\nCC linkages.