Tert-butylamine/oleic acid-assisted morphology tailoring of hierarchical Bi4Ti3O12 architectures and their application for photodegradation of simulated dye wastewater

Herein we report the morphology tailoring of hierarchical Bi4Ti3O12 architectures by using tert-butylamine (TB) and oleic acid (OA). It is demonstrated that the content of TB and OA has an important effect on the morphologies of as-derived Bi4Ti3O12 samples. When adding 12 mmol TB and 6 mmol OA (with respect to 1 mmol Bi4Ti3O12) to the precursor solution, rod-like hierarchical architectures (length 2–15 μm, diameter 0.5–1.7 μm) are obtained. The hierarchical microrods are composed of nanosheets of 20–50 nm in thickness and 300–1700 nm in diameter. The addition of other amounts of TB and OA results in the formation of nanoflake-assembled hierarchical hollow microspheres with size of several micrometres; however the sizes of the microspheres and their sub-nanoflakes depend on the TB/OA amounts. Rhodamine B (RhB), methyl orange (MO) and methylene blue (MB) aqueous solutions, as well as RhB/MO/MB mixture solution (simulated dye wastewater), were used to evaluate the photodegradation performances of the as-prepared Bi4Ti3O12 samples under simulated sunlight irradiation. It is demonstrated that the nanosheet-assembled hierarchical microrods possess a photodegradation activity preponderating over the other morphologies. Moreover, the photocatalytic experiments reveal an interesting photodegradation process of RhB/MO/MB in the mixture solution, which is different from the photodegradation of single dye solution. The photodegradation mechanism of the Bi4Ti3O12 photocatalysts was investigated and discussed.