Metal‐free covalent organic frameworks (COFs) are employed in oxygen reduction reactions (ORR) because of their diverse structural units and controllable catalytic sites, and the edge sites have high catalytic activity than the basal sites. However, it is still challenge to modulate the edge sites in COFs, because the extended frameworks in two‐ or three‐dimensional topologies resulted in limited edge parts. In this study, we have demonstrated the edge site modulation engineering based on one dimensional (1D) COFs to catalyze the ORR, which featured distinct edge groups‐carbonyl, diaminopyrazine, phenylimidazole, and benzaldehyde imidazole units. The synthesized COFs had same ordered frameworks, similar pore structure, but had different electronic states of the carbons along the edge sites, which results in tailored catalytic properties. Notably, the COF functionalized with a phenylimidazole edge group exhibited superior catalytic performance compared to the other synthesized COFs. And the theoretical calculation further revealed the different edge sites have tunable binding ability of the intermediates OOH*, which contributed modulated activity. Our findings introduce a novel way for designing COFs optimized for ORR applications through molecular level control of edge sites.

中文翻译：

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氧还原反应的一维共价有机框架中的催化边缘


无金属共价有机骨架（COF）因其多样化的结构单元和可控的催化位点而被用于氧还原反应（ORR），并且边缘位点比基础位点具有更高的催化活性。然而，调节 COF 中的边缘位置仍然是一个挑战，因为二维或三维拓扑中的扩展框架导致边缘部分有限。在这项研究中，我们展示了基于一维（1D）COF的边缘位点调制工程来催化ORR，其具有独特的边缘基团——羰基、二氨基吡嗪、苯基咪唑和苯甲醛咪唑单元。合成的COF具有相同的有序框架、相似的孔结构，但沿边缘位置的碳具有不同的电子态，从而产生定制的催化性能。值得注意的是，与其他合成的COF相比，用苯基咪唑边缘基团功能化的COF表现出优异的催化性能。理论计算进一步揭示了不同的边缘位点对中间体OOH*具有可调节的结合能力，从而有助于调节活性。我们的研究结果介绍了一种通过边缘位点的分子水平控制来设计针对 ORR 应用优化的 COF 的新方法。