Chen Mengyuan, Zhu Zhiqiang, Ji Youxin, Kong Xiangtao, Han Diandian, Zhai Lipeng
National Engineering Research Center for Advanced Polymer Processing Technology, The Key Laboratory of Material Processing and Mold of Ministry of Education, College of Materials Science and Engineering, Zhengzhou University Zhengzhou 450002 P. R. China
Department Henan Key Laboratory of Functional Salt Materials, Center for Advanced Materials Research, Zhongyuan University of Technology Zhengzhou 450007 P. R. China
Chem Sci. 2025 May 26;16(25):11669-11677. doi: 10.1039/d5sc02145f. eCollection 2025 Jun 25.
Metal-free covalent organic framework (COF) materials are promising catalysts for the oxygen reduction reaction (ORR). However, it is difficult to markedly modulate their catalytic performance by only changing the side groups because their partially conjugated linkages weaken the influence of the electronic and charge transfer properties along the frameworks. Here, we demonstrated the amplification effect of micro-changes in the side units of COFs by constructing imidazole linkages for the ORR, and four different electron effect groups (H, F, OMe, and OH) were introduced. Owing to the conjugated linkages, electronic effects can be transmitted to the active sites through the skeleton. Notably, the half-wave potential ( ) and mass activity of OH-COF were 0.80 V RHE and 12.43 A g, respectively, which were 180 mV more positive and 11 times more than those of H-COF, indicating the superior catalytic activity of OH-COF. Theoretical calculations revealed that different side groups influenced the binding ability of the intermediates and thus contributed to the modulated catalytic properties. This work demonstrates that a small change in the pore surface leads to substantial variations in the electrocatalytic performance, offering valuable insights into the relationship between the structural design and performance of COFs as electrocatalysts.
无金属共价有机框架（COF）材料是用于氧还原反应（ORR）的有前景的催化剂。然而，仅通过改变侧基来显著调节其催化性能是困难的，因为它们的部分共轭键会削弱沿框架的电子和电荷转移性质的影响。在此，我们通过构建用于ORR的咪唑键展示了COF侧单元微小变化的放大效应，并引入了四个不同的电子效应基团（H、F、OMe和OH）。由于共轭键，电子效应可以通过骨架传递到活性位点。值得注意的是，OH-COF的半波电位（ ）和质量活性分别为0.80 V（相对于可逆氢电极，RHE）和12.43 A g，比H-COF的半波电位正180 mV，质量活性高11倍，表明OH-COF具有优异的催化活性。理论计算表明，不同的侧基影响中间体的结合能力，从而导致催化性能的调节。这项工作表明，孔表面的微小变化会导致电催化性能的显著变化，为COF作为电催化剂的结构设计与性能之间的关系提供了有价值的见解。
