Dramatic activity of a Bi2WO6@g-C3N4 photocatalyst with a core@shell structure

Here we report a Bi2WO6@g-C3N4 core@shell structure which was prepared by a combined ultrasonication-chemisorption method with enhanced photocatalytic degradation. The composites were extensively characterized by X-ray diffraction (XRD), Fourier transform infrared spectra (FTIR), scanning electron microscopy (SEM), transmission electron microscopy (TEM) and UV-vis diffuse reflectance spectroscopy (DRS). Compared with bare Bi2WO6 and g-C3N4, the Bi2WO6@g-C3N4 composites exhibited significantly enhanced photocatalytic activity for methylene blue (MB) degradation under visible light irradiation. The 3 wt% Bi2WO6@g-C3N4 showed the highest photocatalytic activity under visible light irradiation, which was about 1.97 times higher than Bi2WO6. In addition, the quenching effects of different scavengers displayed that the reactive h(+) and O-center dot(2)- play the major role in the MB decolorization. The core@shell hybrid photocatalyst exhibited dramatically enhanced photo-induced electron-hole separation efficiency, which was confirmed by the results of photocurrent and EIS measurements. On the basis of the experimental results and estimated energy band positions, a mechanism for the enhanced photocatalytic activity was proposed.