Custom‐Design of Strong Electron/Proton Extractor on COFs for Efficient Photocatalytic H₂O₂ Production

Abstract

The development of photocatalysts with continuous electron extraction and rapid proton transfer could kinetically accelerate the artificial photosynthesis, but remains a challenge. Herein, we report the topology‐guided synthesis of a high‐crystalline triazine covalent organic framework (COF) decorated by uniformly distributed polar oxygen functional groups (sulfonic group or carboxyl) as the strong electron/proton extractor for efficient photocatalytic H2O2 production. It was found that the polarity‐based proton transfer as well as electron enrichment in as‐obtained COFs played a crucial role in improving the H2O2 photosynthesis efficiency (i.e., with an activity order of sulfonic acid‐ (SO3H‐COF) > carboxyl‐ (COOH‐COF) > hydrogen‐ (H‐COF) functionalized COFs). The strong polar sulfonic acid group in the high‐crystalline SO3H‐COF triggered a well‐oriented built‐in electric field and more hydrophilic surface, which serves as an efficient carrier extractor enabling a continuous transportation of the photogenerated electrons and interfacial proton to the active sites (i.e., C atoms linked to ‐SO3H group). As‐accelerated proton‐coupled electron transfer (PCET), together with the stabilized O2 adsorption finally leads to the highest H2O2 production rate of 4971 μmol g‐1 h‐1 under visible light irradiation. Meanwhile, a quantum yield of 15% at 400 nm is obtained, superior to most reported COF‐based photocatalysts.