Visible-light-induced WO3/g-C3N4 composites with enhanced photocatalytic activity

Abstract

Novel WO₃/g-C₃N₄ composite photocatalysts were prepared by a calcination process with different mass contents of WO₃. The photocatalysts were characterized by thermogravimetric analysis (TG), powder X-ray diffraction (XRD), scanning electron microscopy (SEM) and energy dispersive X-ray spectrometry (EDS), high-resolution transmission electron microscopy (HRTEM), UV-vis diffuse reflection spectroscopy (DRS), X-ray photoelectron spectroscopy (XPS), photoluminescence (PL) and electrochemical impedance spectroscopy (EIS). The photocatalytic activity of the photocatalysts was evaluated by degradation of methylene blue (MB) dye and 4-chlorophenol (4-CP) under visible light. The results indicated that the WO₃/g-C₃N₄ composite photocatalysts showed higher photocatalytic activity than both the pure WO₃ and pure g-C₃N₄. The optimum photocatalytic activity of WO₃/g-C₃N₄ at a WO₃ mass content of 9.7% under visible light irradiation was up to 4.2 times and 2.9 times as high as that of the pure WO₃ and pure g-C₃N₄, respectively. The remarkably increased performance of WO₃/g-C₃N₄ was mainly attributed to the synergistic effect between the interface of WO₃ and g-C₃N₄, including enhanced optical absorption in the visible region, enlarged specific surface areas and the suitable band positions of WO₃/g-C₃N₄ composites.