Dramatic activity of a Bi2WO6@g-C3N4 photocatalyst with a core@shell structure
Abstract
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 ˙O2− 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.