Novel ternary g -C 3 N 4 /Fe 3 O 4 /Ag 2 CrO 4 nanocomposites: magnetically separable and visible-light-driven photocatalysts for degradation of water pollutants

Novel magnetically separable g-C3N4/Fe3O4/Ag2CrO4 nanocomposites, as visible-light-driven photocatalysts, were prepared using a facile refluxing method with no require to any additives or post preparation treatments. The resultant samples were characterized by XRD, EDX, TEM, UV–vis DRS, FT–IR, TGA, PL, and VSM techniques. The photocatalytic activities of the resultant samples were investigated by degradation of rhodamine B in aqueous solution under visible-light illumination. The results showed that the g-C3N4/Fe3O4/Ag2CrO4 (20%) nanocomposite exhibited superior activity. Photocatalytic activity of this nanocomposite was about 6.3 and 5-fold higher than those of the g-C3N4 and g-C3N4/Fe3O4 samples, respectively. The highly enhanced activity was attributed to more absorption of the nanocomposites in visible range and efficient separation of the charge carriers. Furthermore, we investigated the influence of refluxing time, calcination temperature, and scavengers of the reactive species on the degradation activity. It was found that superoxide ions are the primary reactive species to cause the degradation reaction over the ternary nanocomposite. Besides, stability of the magnetic nanocomposite was tested by five recycling experiments.