A highly fluorine-functionalized 2D covalent organic framework for promoting photocatalytic hydrogen evolution

摘要

In search of novel semiconductor photocatalysts is one of the important topics in photocatalytic solar fuel production. Here, we report a novel highly fluorinated covalent organic framework (denoted as TFA-COF) constructed via Schiff-base condensation of 2,3,5,6-tetrafluoroterephthaldehyde and 2,4,6-tris(4-aminophenyl)-1,3,5-triazine for photocatalytic H-2 production from water. Introducing fluorine atoms with electron-withdrawing ability into the framework of COF can not only significantly increase its specific surface area to 2490.3 m(2)/g, but also reduce its band gap, and bring about the efficient separation of photogenerated electrons and holes. As a result, the TFA-COF exhibits a continuous and stable photocatalytic H-2 production rate of 80 mol.g(-1).h(-1) under full wavelength irradiation, which is much higher than that of the similar one without fluorine (TA-COF, 10 mol.g(-1)-h(-1)). Our results illustrate that the introduction of fluorine atoms can effectively increase the photocatalytic performance of COFs.