Synthesis and characterization of g-C3N4/Bi2MoO6 heterojunctions with enhanced visible light photocatalytic activity

Heterojunctions of graphitic carbon nitride (g-C 3 N 4 ) and Bi 2 MoO 6 were solvothermally synthesized and characterized by X-ray diffraction, Fourier transform-infrared spectroscopy, X-ray photoelectron spectroscopy, scanning electron microscopy, transmission electron microscopy (TEM) and high resolution TEM. The photocatalytic degradation activity of the g-C 3 N 4 /Bi 2 MoO 6 composites for Rhodamine B was examined under visible light irradiation. The heterojunction composites exhibited higher photocatalytic activity than pure g-C 3 N 4 or Bi 2 MoO 6 . The photocatalytic activity of the composites increased then decreased with increasing Bi 2 MoO 6 content. The g-C 3 N 4 /Bi 2 MoO 6 heterojunction with a Bi 2 MoO 6 content of 16.1   wt.% exhibited the highest photocatalytic activity, and its photocatalytic efficiency was more than three times those of pure g-C 3 N 4 or Bi 2 MoO 6 . The enhanced photocatalytic activity of the g-C 3 N 4 /Bi 2 MoO 6 heterostructure photocatalyst was attributed predominantly to the efficient separation of photoinduced electrons and holes. The g-C 3 N 4 /Bi 2 MoO 6 heterojunction photocatalyst exhibited excellent stability and reusability. A detailed mechanism for the enhanced photocatalytic activity is discussed. Superoxide radicals were the major active species. This study provides a visible light responsive photocatalyst with potential in environmental remediation applications.