Novel g-C3N4/Ag2SO4 nanocomposites: Fast microwave-assisted preparation and enhanced photocatalytic performance towards degradation of organic pollutants under visible light

Graphite carbon nitride (g-C3N4)/Ag2SO4 nanocomposites, as highly enhanced visible-light-driven photo catalysts, were prepared by a fast microwave-assisted method. The resulting g-C3N4/Ag2SO4 nanocomposites were characterized by X-ray diffraction, energy dispersive analysis of X-rays, scanning electron microscopy, transmission electron microscopy, thermogravimetric analysis, Fourier transform-infrared spectroscopy, and ultraviolet-visible diffuse reflectance spectroscopy techniques. Moreover, charge separation efficiency was studied by photoluminescence measurements. Photocatalytic activity of the g-C3N4/Ag2SO4 (40%) nanocomposite in degradation of rhodamine B, methylene blue, and fuchsine is about 6, 3.8, and 3.3-folds greater than that of the g-C3N4 under visible-light illumination. Effect of microwave irradiation time, calcination temperature, and scavengers of the reactive species on the degradation reaction was also evaluated. The enhanced photocatalytic activity was mainly ascribed to the matching band energies of g-C3N4 and Ag2SO4 which leads to an improved separation of photogenerated electron hole pairs. Finally, the optimized nanocomposite was recycled for five times without remarkable decrease of the photocatalytic activity. (C) 2016 Elsevier Inc. All rights reserved.