English
Developing photocatalysts with continuous electron extraction and rapid proton transfer can dynamically accelerate artificial photosynthesis, but this remains a challenge. In this article, we report a topology guided synthesis of highly crystalline triazine covalent organic frameworks (COFs) with uniformly distributed polar oxygen functional groups (sulfonic acid or carboxyl groups), which can be used as strong electron/proton extractants for efficient photocatalytic production of H2O2. Research has found that polarity based proton transfer and electron enrichment in the obtained COF play a crucial role in improving the efficiency of H2O2 photosynthesis (i.e., the activity order is sulfonic acid - (SO3H-COF)>carboxyl - (COOH-COF)>hydrogen - (H-COF) functionalized COF). The strong polar sulfonic acid groups in highly crystalline SO3H-COF trigger a well oriented built-in electric field and a more hydrophilic surface, which can serve as an efficient carrier extractor to continuously transport photo generated electrons and interface protons to the active site (i.e. the C atom connected to the - SO3H group). Accelerated proton coupled electron transfer (PCET) and stable O2 adsorption ultimately result in a maximum H2O2 generation rate of 4971 μ mol g-1 h-1 under visible light irradiation. Meanwhile, a quantum yield of 15% was achieved at 400 nm, which is superior to most reported COF based photocatalysts.
