Hybrid BiOBr–TiO2 nanocomposites with high visible light photocatalytic activity for water treatment

Graphical abstract: A hybrid BiOBr–TiO2 nanocomposite, with large surface area and opened mesoporous structure, exhibits high visible-light photocatalytic performance, and the photodegradation of RhB is initiated by both ·O2− and hVB+. -- Highlights: • BiOBr–TiO2 hybrids exhibit large surface area and opened mesoporous structure. • Introduced amorphous TiO2 can prevent agglomeration of BiOBr nanoparticles. • The hybrid exhibits superior visible light photocatalytic performance. • BiOBr–TiO2 is easily separated by sedimentation due to 3D superstructure. -- Abstract: Novel highly active visible light photocatalysts BiOBr–TiO2 nanocomposites were prepared by a facile one-pot solvothermal approach. Series of characterizations verified that the BiOBr nanoscale crystals are highly dispersed in amorphous TiO2 to form the hybrid mesoporous structure. The material shows excellent photocatalytic performance towards photodegradation of Rhodamine B under visible light irradiation. The content ratio between TiO2 and BiOBr plays a key role in the microstructure of the nanocomposites, so as to result in distinguished photocatalytic activity. The sample with a molar ratio of 10 between TiO2 and BiOBr shows the optimum performance. The high photocatalytic activity of BiOBr–TiO2 nanocomposites under visible light could be ascribed to the large surface area, opened mesoporous structure, appropriate band-gap, as well as synergistic effect between TiO2 and BiOBr. Besides, the BiOBr–TiO2 composites render a facile separation due to the three-dimensional superstructure. The BiOBr–TiO2 photocatalyst is very promising for water purification as well as other environmental applications