Novel g-C3N4/graphene/NiFe2O4 nanocomposites as magnetically separable visible light driven photocatalysts

Abstract

Magnetically separable all-solid-state Z-scheme g-C3N4/graphene/NiFe2O4 (CGN) nanocomposites have been synthesized using one pot hydrothermal method. The as-prepared pristine and nanocomposite samples were characterized using X-ray diffraction (XRD), fourier transform infrared spectroscopy (FTIR), UV–VIS diffuse reflectance spectroscopy (DRS), photoluminescence (PL) spectroscopy, scanning electron microscopy (SEM), energy dispersive x-ray spectroscopy (EDS), transmission electron microscopy (TEM), high resolution transmission electron microscopy (HRTEM), X-ray photoelectron spectroscopy (XPS), Brunauer-Emmett-Teller (BET) surface analysis, and Vibrational sample magnetometer (VSM) characterization techniques. The result reveals that the weight percent of NiFe2O4 have considerable effect on the optical property and photocatalytic activity of the nanocomposites. The CGN-25% nanocomposite shows the best photocatalytic activity and its activity is about 15, 7 and 6 folds higher than those of NiFe2O4, g-C3N4, and CN-25% respectively on the degradation of methyl orange (MO). This enhancement could be attributed to the synergistic effect between g-C3N4, graphene and NiFe2O4, which could accelerate photogenerated electron-hole separation and prolong the life of the photo-induced carriers to enhance their activity. The CGN-25% was recycled using magnet without significant loss and shows almost the same photocatalytic performance for six runs. Moreover, a possible photocatalytic mechanism was proposed. This could provide new insights to develop highly efficient and stable g-C3N4 and graphene based magnetic photocatalysts.