Integration of NiWO4 and Fe3O4 with graphitic carbon nitride to fabricate novel magnetically recoverable visible-light-driven photocatalysts

Novel magnetically recoverable g-C3N4/Fe3O4/NiWO4 (gCN/M/NiWO4) nanocomposites, with superior visible-light photocatalytic performance, were successfully fabricated by a refluxing calcination method. These hybrid photocatalysts were characterized fairly in terms of the structure, composition, morphology, electronic, textural, thermal, and magnetic properties using XRD, EDX, SEM, TEM, HRTEM, FT-IR, UV–vis DRS, PL, N2 adsorption–desorption, TG, and VSM analyses. Also, the degradation intermediates were identified using gas chromatography–mass spectroscopy. These photocatalysts displayed excellent photocatalytic performance under visible light for degradations of RhB, MB, MO, fuchsine, and phenol pollutants, and they can be recycled by magnetic separation without major loss of activity. The highest photocatalytic efficiency was observed when the sample refluxed for 60 min and calcined at 450 °C for 3 h with 30 wt% NiWO4 content. Activity of this photocatalyst is greater than the pristine gCN by a factor of almost 12, 30, 52, 100, and 6 toward degradations of RhB, MB, MO, fuchsine, and phenol, respectively. Finally, the proposed mechanism for the superior performance of gCN/M/NiWO4 hybrid photocatalysts was discussed.