Construction of dual-channel charge transfer over Bi/BiOBr/BNQDs photocatalyst system toward boosting tetracycline degradation

Abstract

In order to mitigate the negative impact of tetracycline (TC) abuse on the environment, it is essential to explore a green and sustainable photocatalyst for treating antibiotic wastewater. Herein, the BiOBr (BOB) nanosheets decorated by semimetal Bi and BN quantum dots (BNQDs) were prepared successfully. The dual cocatalysts Bi and BNQDs, which possessed capabilities to attract electrons and holes respectively, established a dual-channel for charge carriers transport on BOB nanosheets, thus promoting the separation of photogenerated carriers. Furthermore, the BOB nanosheets with large areas could shorten the charge transfer distance and further accelerate the charge migration to prevent the recombination of photocarriers. Notably, the 4BBOB/3BNQDs samples exhibited an efficient degradation rate (0.0295 min−1) and sterling reusability for photocatalytic removal of TC. The results of photoluminescence spectra and time-resolved photoluminescence spectroscopy indicated that the construction of a dual-channel elevated the charge separation efficiency and prolonged the lifetime of carriers. The rational reaction mechanism was speculated through the analysis of trapping experimental results and the energy band structure. This research opens up a promising avenue to facilitate charge transfer and provides a new perspective for the separation of photoinduced electron-hole pairs.