Assembly of WO3 nanosheets/Bi24O31Br10 nanosheets composites with superior photocatalytic activity for degradation of tetracycline hydrochloride.

In this work, a high-performance composite photocatalyst composed of WO3 nanosheets and Bi24O31Br10 nanosheets was successfully synthesized. The photocatalytic activity of the obtained samples was studied by the degradation of tetracycline hydrochloride under visible light irradiation. The results showed that Bi24O31Br10 modified with the appropriate amount of WO3 nanosheet exhibits higher catalytic activity and stability during the photocatalytic processes, and the holes (h+) is involved in the photolysis reaction as the main active species. The crystallization, morphology, optical and electrochemical properties of the as-prepared composite photocatalyst were characterized, and the mechanism of high photocatalytic activity was also explored. The optimal sample (10%-WO3/Bi24O31Br10) exhibited the best performance for tetracycline hydrochloride (TC) degradation, and more than 80% of the TC was degraded after 60 min under light irradiation. The degradation rate constant k was about 3.34-fold and 1.54-fold higher than pure WO3 and Bi24O31Br10, respectively. Its high photocatalytic performance can be attributed to the following reasons: the appropriate conduction band and valence band positions between WO3 and Bi24O31Br10, the close contact between the two visible light-driven photocatalysts, and the effective separation of the spatial charge. Our work may help to further expand the potential application of oxygen-rich bismuth oxyhalides photocatalyst in wastewater treatment, and provide a new strategy for the modification of nanostructured photocatalysts. [ABSTRACT FROM AUTHOR]