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.