Precise and controllable tandem strategy triggering boosted oxygen reduction activity

摘要

The development of efficient and cost-effective metal-free electrocatalysts for oxygen reduction reaction (ORR) has become crucial for electrochemical energy systems. However, reasonably validating and precisely regulating the active sites for designing optimized materials are still challenging. Herein, we report a precise and controllable tandem strategy to boost the ORR activity based on metal-free covalent organic frameworks (MFCOFs) comprising imine-N, thiophene-S, or triazine-N. Among these MFCOFs, post-tandem BTT-TAT-COF structure displayed a more positive catalytic capability and excellent electrochemical stability, indicating that the synergistic catalysis of multiple active sites induced the ORR catalytic activity through the conjugated skeleton of the structure. Density-functional theory calculations suggest that the series-connected backbone contained highly effective electrocatalytic active centers and provided synergistic catalysis. More importantly, this strategy highlights new opportunities for the advancement of efficient COF-based metal-free ORR catalysts.

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