Electrochemical reduction of carbon dioxide is significant for carbon-neutral clean energy. Catalytic covalent organic frameworks (COFs) constructed with metalloporphyrin skeletons are an ideal alternative for transformation of carbon dioxide to carbon monoxide. However, the strong hydrophobicity and the poor electron-transfer ability of the COFs limit their catalytic performance. Herein, a crown ether and cobalt-porphyrin-based COF (TAPP(Co)-B18C6-COF) has been developed to catalyze carbon dioxide reduction. The crown ether units integrated in the COFs not only enhance the hydrophilicity of the frameworks but also promote the electron transfer from crown ether to the Co-porphyrin cores. In addition, the crown ether units enhance the binding ability of carbon dioxide. By virtue of these features, the catalytic COF showed remarkable catalytic performance with Faradaic efficiencies (FE_CO) of 84.4–93.2% at applied potentials between −0.60 and −0.90 V vs RHE, with the maximum TOF of 1267 h^–1 at −0.9 V. This work provides new insights into COFs and electrocatalysis.

中文翻译：

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构建用于 CO2 电还原的催化冠醚基共价有机骨架

二氧化碳的电化学还原对于碳中和清洁能源具有重要意义。由金属卟啉骨架构建的催化共价有机框架 (COF) 是将二氧化碳转化为一氧化碳的理想替代品。然而，COFs 的强疏水性和较差的电子转移能力限制了它​​们的催化性能。在此，已开发出一种冠醚和钴卟啉基 COF（TAPP(Co)-B18C6-COF）来催化二氧化碳还原。集成在 COF 中的冠醚单元不仅增强了骨架的亲水性，还促进了电子从冠醚转移到钴卟啉核。此外，冠醚单元增强了二氧化碳的结合能力。凭借这些特点，_CO ) 在 -0.60 和 -0.90 V 与 RHE 之间的外加电位下为 84.4–93.2%，在 -0.9 V时的最大 TOF 为 1267 h ^–1。这项工作提供了对 COF 和电催化的新见解。