Template-free and morphology-controlled hydrothermal growth of single-crystalline Bi12TiO20 with excellent simulated sunlight photocatalytic activity

Abstract

Single-crystalline bismuth titanates (Bi₁₂TiO₂₀) with the cubic phase and various morphologies (flower-, belt-, tetrahedral-like) were controllably fabricated by using a mild template-free hydrothermal process. The samples were fully characterized by X-ray diffraction (XRD), field emission scanning electron microscopy (FESEM), transmission electron microscopy (TEM), high-resolution TEM, nitrogen porosimetry measurement, UV-vis diffuse reflectance spectroscopy (DRS), and X-ray photoelectron spectroscopy (XPS). The influence of the solvent and the concentration of NO₃⁻ in the reaction system on the crystallinity and morphology of the Bi₁₂TiO₂₀ samples was investigated in detail. Bi₁₂TiO₂₀ crystals were used as the sunlight-driven photocatalysts to degrade aqueous dye methyl orange (MO) and p-nitrophenol (PNP), and the influence of Bi₁₂TiO₂₀ morphology on the photocatalytic activity was discussed. Finally, the recyclability of Bi₁₂TiO₂₀ was evaluated through three consecutive runs.