Bromine Atoms Decorated Pyene-based Covalent Organic Frameworks for Accelerated Photocatalytic H2 Production.

Abstract

Designing materials with low exciton binding energy is an efficient way of improving the hydrogen production performance of COFs（Covalent Organic Frameworks. Here, it is demonstrated that the strategy of decorating bromine atoms on Pyene-based COFs can achieve elevated photocatalytic H2 evolution rates (HER = 13.61mmol g-1 h-1 ). Low-temperature fluorescence and time-resolved fluorescence spectroscopy (TRPL) indicate that the introduction of bromine atoms can significantly suppress charge recombination. DFT (Density Functional Theory) calculation clarified that the C atoms adjacent to Br are the active sites with a reduced energy barrier in the process of formatting H intermediate species (H*). The modification strategy of Br atoms in COF furnishes a new medium for exploiting exquisite photocatalysts.