Fabrication of BiVO4@g-C3N4(100) heterojunction with enhanced photocatalytic visible-light-driven activity

The BiVO4@g-C3N4(100) heterojunction composites with increased visible-light response were synthesized by a simple hydrothermal method. The as-prepared composites were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), UV-vis diffuse reflectance spectroscopy (DRS), X-ray photoelectron spectroscopy (XPS), fourier transform infrared spectroscopy (FT-IR), raman spectra, N-2 absorption-desorption isotherm (BET), thermogravimetric analysis (TGA) and transmission electron microscopy (TEM). The TEM images show a clear interface between BiVO4(121) and g-C3N4(100), indicating that heterojunction between BiVO4 and g-C3N4 was formed after hydrothermal reaction. The photocatalytic activities of samples were investigated by studying the degradation of RhB under simulated visible-light irradiation (lambda >= 420 nm). It was found that the 10 wt% BiVO4@g-C3N4 exhibited the highest photocatalytic performance, the photodegradation rate is 2.36 and 30.58 times higher than that of either single-phase g-C3N4 or BiVO4. In addition, radicals trapping experiments demonstrated that h(+) and center dot O-2(-) are the main active species while center dot OH could be negligible in the photocatalytic oxidation of RhB solution.