Host-Guest-Induced Electronic State Triggers Two-Electron Oxygen Reduction Electrocatalysis

Abstract

Supramolecular polymers hold promising application prospects in catalysis due to their distinctive molecular recognition and dynamic crosslinking features. However, investigating supramolecular organic electrocatalysts with high efficiency in oxygen reduction reaction (ORR) to hydrogen peroxide (ORHP) remains an unexplored frontier. Herein, we present organic polymers for ORHP by introducing cyclodextrin-containing noncovalent building blocks, and the skeleton electronic environment is further regulated via a host-guest chemistry strategy, affording HG-CD-Ph and HG-CD-TPB with abundant dynamic bonds. The oxygen intermediate desorption and electronic states are well-modulated through the host-guest decoration, resulting in appropriate regional electron binding force and controllable chemical activity. Notably, the introduction of supramolecular host-guest units into the polymer model P-CN-Ph achieves an ultra-high production rate of 9.14 mol g−1 cat h−1, and demonstrates an excellent Faraday efficiency of 98.01%, surpassing most reported metal-free electrocatalysts. Supported by theory calculation and in situ FT-IR experiment, it is revealed that C atoms (site–1) adjacent to –C=N (N) group are potential active sites. Moreover, the dynamic bonds in supramolecular catalysts can effectively regulate the binding ability of oxygen and its intermediates, leading to high reactivity and selectivity for the 2e− ORR. This work pioneers host-guest strategy and provides inspiring ideas for the ORHP process.