Synthesis of novel and stable g-C(3)N(4)-Bi(2)WO(6) hybrid nanocomposites and their enhanced photocatalytic activity under visible light irradiation

Graphitic carbon nitride (g-C(3)N(4)) nanosheets with a thickness of only a few nanometres were obtained by a facile deammoniation treatment of bulk g-C(3)N(4) and were further hybridized with Bi(2)WO(6) nanoparticles on the surface via a solvothermal method. The composite photocatalysts were characterized by powder X-ray diffraction, scanning electron microscopy, transmission electron microscopy, UV–vis diffuse reflection spectroscopy and X-ray photoelectron spectroscopy (XPS). The HR-TEM results show that the nano-sized Bi(2)WO(6) particles were finely distributed on g-C(3)N(4) sheet surface, which forms heterojunction structure. The UV–vis diffuse reflectance spectra (DRS) show that the absorption edge of composite photocatalysts shifts towards lower energy region in comparison with those of pure g-C(3)N(4) and Bi(2)WO(6). The degradation of methyl orange (MO) tests reveals that the optimum activity of 8 : 2 g-C(3)N(4)-Bi(2)WO(6) photocatalyst is almost 2.7 and 8.5 times higher than those of individual g-C(3)N(4) and Bi(2)WO(6). Moreover, the recycle experiments depict high stability of the composite photocatalysts. Through the study of the influencing factors, a possible photocatalytic mechanism is proposed. The enhancement in both photocatalytic performance and stability was caused by the synergistic effect, including the effective separation of the photogenerated electron-hole pairs at the interface of g-C(3)N(4) and Bi(2)WO(6), the smaller the particle size and the relatively larger specific surface area of the composite photocatalyst.