Covalent Triazine Framework Modified BiOBr Nanoflake with Enhanced Photocatalytic Activity for Antibiotic Removal

The development of photocatalysts based on covalent organic frameworks (COFs) is intriguing research due to their structural flexibility and tremendous catalytic sites. Herein we demonstrate a facile strategy to prepare composite materials of combined COFs and inorganic semiconductors with enhanced photocatalytic performances. A new composite photocatalyst (BiOBr/CTF-3D) integrated three-dimensional (3D) covalent triazine framework (CTF-3D) with two-dimensional BiOBr nanoflake was prepared via a simple coprecipitation method. The structural characterizations demonstrated that the amorphous CTF-3D was well modified on the surfaces of BiOBr. The photocatalytic activity of the BiOBr/CTF-3D composite was evaluated by the degradation of colorless antibiotic agents, tetracycline hydrochloride (TC) and ciprofloxacin (CIP), under visible light irradiation. When the mass percent of CTF-3D was 2%, the BiOBr/CTF-3D composite displayed the highest photocatalytic activity. The enhancement of photocatalytic performance was mainly derived from the enlarged optical adsorption range, the efficiently separated photogenerated electron–hole pairs, and the accelerated adsorption and transfer of antibiotic molecules, in the synergistically facilitating photocatalytic process. In addition, a possible photocatalytic mechanism for degrading TC by BiOBr/CTF-3D-2% was tentatively proposed. This work opens up a new strategy to improve the photocatalytic activity of traditional inorganic photocatalysts by modification with COFs materials for solving the pollution of living ecosystems.