Amidoxime-Functionalized sp-Carbon-Conjugated Covalent Organic Frameworks for Overall Photocatalytic Hydrogen Peroxide Production.

Cyano-functionalized sp-carbon-conjugated covalent organic frameworks (CN-COFs) have been considered as promising candidates for artificial photosynthesis of hydrogen peroxide (HO). Nevertheless, the performance of CN-COFs is inherently limited by constrained oxygen capture capacity, insufficient charge separation, and rapid carrier recombination. Herein, the study rationally reports a strategy for integrating amidoxime groups (AO) into a COF through one-step cyano hydrolysis process to increase photocatalytic HO production. Combined simulations and characterizations reveal that introducing AO groups enhances hydrophilicity, stabilizes adsorbed Oxygen (O) via hydrogen bonding, accelerates the charge separation and transfer, as well as lowers the energy barrier for oxygen reduction reaction pathway, thus achieving an unmatched HO production rate of 6024 µmol h g. Importantly, the solar-to-chemical conversion (SCC) efficiency of PTTN-AO reaches 0.61%, significantly surpassing that of natural plants (≈0.1%) and most COF-based photocatalysts. The current findings are encouraging for the molecular design of polymers for green and efficient HO production.