Preparation of visible light-driven g-C₃N₄@ZnO hybrid photocatalyst via mechanochemistry.

C3N4@ZnO hybrid materials with visible light photocatalytic performance have been prepared by facile mechanical milling. The dispersion of conjugated molecule g-C3N4 on the surface of ZnO improved during mechanical process, and the multilayer hybrid structure of g-C3N4@ZnO materials with remarkable visible light photocatalytic activity was formed by ball milling. The photocatalytic activity and photocurrent intensity of g-C3N4@ZnO under visible light irradiation was 3.0 and 2.0 times higher than those of pure C3N4, respectively. The great enhancement of visible light response originates from the increase of separation and immigration efficiency of photogenerated electron-hole pairs. Furthermore, a synergistic photocatalysis mechanism between ZnO and g-C3N4 was proposed. The enhanced visible light photocatalytic properties originate from the injection of excited electrons from the LUMO of C3N4 to the CB of ZnO. However, the photocatalytic activity of the photocatalyst is much lower than that of ZnO under UV light, which is caused by the lattice defect of ZnO formed during milling.