Fabrication of Z-scheme g-C3N4/RGO/Bi2WO6 photocatalyst with enhanced visible-light photocatalytic activity

An efficient visible-light-driven Z-scheme g -C 3 N 4 /RGO/Bi 2 WO 6 composite was fabricated by the hydrothermal method. The prepared g -C 3 N 4 /RGO/Bi 2 WO 6 composite were characterized by X-ray diffraction (XRD), transmission electron microscopy (TEM), scanning electron microscopy (SEM), nitrogen sorption, Fourier transform infrared spectroscopy (FT-IR), diffuse reflectance spectroscopy (DRS) and X-ray photoelectron spectrometer (XPS). The photocatalytic activity of the g -C 3 N 4 /RGO/Bi 2 WO 6 composite was evaluated by the degradation of 2,4,6-trichlorophenol (TCP) under visible-light irradiation. The photochemical test and scavenging experiment showed the photogenerated electrons (e − ) and holes (h + ) had strong reducing capability and oxidation capability, respectively. The photocatalytic activity of the g -C 3 N 4 /RGO/Bi 2 WO 6 composite was higher than that of the pure g -C 3 N 4 , Bi 2 WO 6 , and g -C 3 N 4 /Bi 2 WO 6 during the TCP degradation, which could be due to the efficient visible-light utilization efficiency and the construction of Z-scheme. RGO served as a charge transmission bridge between the g -C 3 N 4 and the Bi 2 WO 6 , and the Z-scheme kept the electrons with high reducing capability in the conduction band (CB) of g -C 3 N 4 and the holes with high oxidation capability in the valence band (VB) of Bi 2 WO 6 . The photogenerated holes of Bi 2 WO 6 were the major active species in the TCP oxidative degradation, and the photogenerated electrons of g -C 3 N 4 were the major active species in the TCP dechlorination.