A Crystalline Partially Fluorinated Triazine Covalent Organic Framework for Efficient Photosynthesis of Hydrogen Peroxide
Haozhen Wang, Chao Yang, Fangshuai Chen, Gengfeng Zheng, Qing Han
Abstract
Abstract A partially fluorinated, metal‐free, imine‐linked two‐dimensional triazine covalent organic framework (TF 50 ‐COF) photocatalyst was developed. Fluorine (F)‐substituted and nonsubstituted units were integrated in equimolar amounts on the edge aromatic units, where they mediated two‐electron O 2 photoreduction. F‐substitution created an abundance of Lewis acid sites, which regulated the electronic distribution of adjacent carbon atoms and provided highly active sites for O 2 adsorption, and widened the visible‐light‐responsive range of the catalyst, while enhancing charge separation. Varying the proportion of F maximized the interlayer interactions of TF 50 ‐COF, resulting in improved crystallinity with faster carrier transfer and robust photostability. The TF 50 ‐COF catalyst demonstrates high selectivity and stability in O 2 photoreduction into H 2 O 2 , with a high H 2 O 2 yield rate of 1739 μmol h −1 g −1 and a remarkable apparent quantum efficiency of 5.1 % at 400 nm, exceeding the performance of previously reported nonmetal COF‐based photocatalysts.