Mass Production and Photocatalytic Activity of Highly Crystalline Metastable Single-Phase Bi20TiO32 Nanosheets

Highly crystalline metastable bismuth titanate (Bi20TiO32) nanosheets are prepared via a simple green wet chemical route for the first time. The Bi20TiO32 photocatalysts were characterized by transmission electron microscopy (TEM), field emission scanning electron microscopy (FESEM), energy dispersive spectrum analysis (EDS), X-ray diffraction (XRD), N2 adsorption−desorption (BET), and UV−vis diffuse reflectance spectroscopy (DRS). Inspiringly, Bi20TiO32 nanosheets showed high photocatalytic activity for the degradation of nonbiodegradable azo dye under simulated sunlight and visible-light irradiation. The experimental results showed that the photocatalytic activity of the Bi20TiO32 nanosheets was superior to the commercial Degussa P25 TiO2, and demonstrated that the morphology and crystal structure have a distinct effect on the photocatalytic activity. The reasons for the high photocatalytic activity and the formation mechanism of Bi20TiO32 nanosheets are also discussed.