Constructing BiOI-BiOBr/TiO2 nanocomposites by using a double solvothermal method for enhanced photocatalytic activity under visible light irradiation

Fabrication of ternary nanocomposites for boosting photocatalytic activity has attracted growing research interest over the past decades. In this work, a series of BiOI-BiOBr/TiO2 (Bi-I-Bi-Br/Ti-DS) ternary nanocomposites were synthesized by employing a double solvothermal (DS) method. The microstructure, morphology, structural, optical, chemical, and electrochemical properties of the synthesized nanocomposites were systematically studied using various spectroscopic techniques. Their applications for the photocatalytic degradation of rhodamine B (RhB) and tetracycline (TC) under visible light irradiation have been demonstrated. The (1:1) BiOI-BiOBr/TiO2 (Bi-I-Bi-Br/Ti-1(DS)) ternary nanocomposite exhibits 3 times and 1.5 times higher photocatalytic degradation of RhB as compared to bare TiO2 double solvothermal (Ti-DS) and the binary nanocomposites, respectively. Similarly, for the tetracycline degradation, it is 4.4 times higher compared to Ti-DS and 2.1 times higher than binary nanocomposites. Scavenging experiments were carried out to assess the role of active radical species responsible for the degradation of model organic pollutants. A possible reaction mechanism is proposed. Remarkably, the Bi-I-Bi-Br/Ti-1(DS) photocatalyst retained excellent stability even after several cycles. Additionally, the decay studies of EPR signals display nice correlation with the photocatalytic activity. This research sheds light on a promising way to fabricate the highly efficient, stable, and visible-light-driven ternary nanocomposites that can be used as photocatalysts to help clean up the environment using solar energy.