Fabrication and photocatalytic activity enhanced mechanism of direct Z-scheme g-C 3 N 4 /Ag 2 WO 4 photocatalyst

Abstract Herein, a direct Z-scheme graphitic carbon nitride (g-C 3 N 4 )/silver tungstate (Ag 2 WO 4 ) photocatalyst was prepared by a facile in situ precipitation method using g-C 3 N 4 as a support and silver nitrate as a precursor. X-ray diffraction, Fourier transform infrared spectroscopy, X-ray photoelectron spectroscopy, transmission electron microscopy, and elemental mapping demonstrated that β-Ag 2 WO 4 nanoparticles were evenly distributed on the surface of g-C 3 N 4 nanosheets, which acted as a support for the nucleation and growth of β-Ag 2 WO 4 and inhibited the phase transformation of metastable β-Ag 2 WO 4 to stable α-Ag 2 WO 4 . Photocatalytic experiments indicated that the g-C 3 N 4 /Ag 2 WO 4 nanocomposite photocatalyst displayed a better photocatalytic activity than pure g-C 3 N 4 and Ag 2 WO 4 toward the degradation of methyl orange. The enhanced photocatalytic performance of g-C 3 N 4 /Ag 2 WO 4 could be well explained by a direct Z-scheme photocatalytic mechanism. This mechanism was related to the efficient space separation of photogenerated electron–hole pairs and the great oxidation and reduction capabilities of the g-C 3 N 4 /Ag 2 WO 4 system. This work provided new insights into the design and fabrication of g-C 3 N 4 -based direct Z-scheme photocatalysts.