Ce and F Comodification on the Crystal Structure and Enhanced Photocatalytic Activity of Bi₂WO₆ Photocatalyst under Visible Light Irradiation

The novel Ce and F codoped Bi₂WO₆ samples have been successfully obtained by a facile one-step hydrothermal reaction for the first time. They were characterized by X-ray diffraction patterns (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), high-resolution TEM (HRTEM), X-ray photoelectron spectroscopy (XPS), and UV–vis diffuse reflectance spectra (DRS) and photoluminescence (PL) spectra. The presence of Ce³⁺, Ce⁴⁺, and F^– dopants in Bi₂WO₆ was confirmed by XPS. The change of microstructure and optical band gap has also been observed after the doping of Ce and F. Under visible light, the as-synthesized plate-like F–Ce–Bi₂WO₆ sample exhibits a much better visible-light-responsive photocatalytic performance than pure Bi₂WO₆ for the degradation of RhB and photocurrent (PC) generation. The mechanism of high photcatalytic activity was also suggested on the basis of the PL spectra, electrochemical impedance spectra (EIS), and active species trapping measurements. The results indicated that the synergistic effect of the Ce and F dopants is responsible for the efficient separation and migration of photoinduced charge carriers, thus resulting in the remarkably improved photocatalytic activity.