Synthesis and characterization of g-C3N4/Ag3VO4 composites with significantly enhanced visible-light photocatalytic activity for triphenylmethane dye degradation

The g-C3N4/Ag3VO4 hybrid photocatalysts were prepared by Ag3VO4 anchoring on the surface of g-C3N4. The transmission electron microscope, X-ray diffraction, Fourier transform infrared spectroscopy and X-ray photo-electron spectroscopy analyses demonstrated that Ag3VO4 nanoparticles well distributed on the surface of g-C3N4 and the g-C3N4/Ag3VO4 hetero-junctions were formed. Compared with pure g-C3N4 and Ag3VO4, the g-C3N4/Ag3VO4 hybrid materials displayed much higher photocatalytic activity for basic fuchsin degradation (20 mg/L, 50 mL) under visible-light irradiation. The 40 wt% g-C3N4/Ag3VO4 photocatalyst exhibited optimal removal rate constant of 0.92 h(-1), which was 11.5 and 6.6 times higher than that of pure g-C3N4 and Ag3VO4, respectively. Density functional theory calculations indicated that complementary conduction and valence band-edge hybridization between g-C3N4 and Ag3VO4 could apparently increase separation efficiency of electron-hole pairs of g-C3N4/Ag3VO4 composites, which was confirmed by photoluminescence spectra. In addition, it was found that h(+) and center dot O-2(-1) generated in the photocatalytic process played a key role in basic fuchsin degradation. (C) 2013 Elsevier B.V. All rights reserved.