Visible-Light-Induced Self-Cleaning Property of Bi2Ti2O7-TiO2 Composite Nanowire Arrays

Bi2Ti2O7-TiO2 composite nano:wire arrays were prepared via a two-step sequential solvothermal and subsequent calcination process. The, morphology and structure of the Bi2Ti2O7-TiO2 composite nanowire array composite were Characterized by X-ray diffraction, field emission scanning election microscopy, and transmission electron microscopy. The UV-visible diffuse reflectance spectroscopy analysis indicated that the absorption spectrum of the Bi2Ti2O7-TiO2 composite nanowire array composite was extended to the visible light region due to the existence of Bi2Ti2O7. The Bi2Ti2O7-TiO2 composite nanowire arrays exhibit superhydrophilicity with water,contact angles of 0 degrees after irradiation With visible, light, and the superhydrophilic nature is retained for at least 15 days. This effect enables us to consider self-cleaning applications that do not require permanent UV exposure: Compared to pure Bi2Ti2O7 and TiO2, the vertically aligned Bi2Ti2O7-TiO2 composite nanowire arrays Showed; more significant visible light self-cleaning performance due to the synergistic effect of superhydrophilicity and significant photocatalytic activity caused by effective electron hole separation at the interfaces of the two semiconductors; which was confirmed by the electrochemical analysis and surface photovoltage technique.