Hydrothermal synthesis and photocatalytic property of Bi₂MoO₆/ZnO composite material

The Bi₂MoO₆/ZnO composite has been successfully synthesized by a hydrothermal method. As-prepared Bi₂MoO₆, ZnO, Bi₂MoO₆/ZnO samples were characterized by X-ray diffraction, scanning electron microscopy, UV-visible and Raman spectroscopy. The results show that the crystals of different substances grow independently. The highly crystalline ZnO with a hexagonal wurtzite structure is embedded into the Bi₂MoO₆ matrix of a bismuth-layer orthorhombic structure. The aggregation of Bi₂MoO₆ particles are greatly reduced and particles with a small grain size can be finally obtained with the addition of ZnO. This morphology provides the additional surface area and thus permits the Bi₂MoO₆ particles to contact with the ZnO. The band gap of Bi₂MoO₆/ZnO composite material is estimated as 2.25 eV. The low band gap is attributed to the morphology and microstructure of Bi₂MoO₆/ZnO. Compared to pure ZnO, the valence band is widened and the conduction band is elevated, so the Bi₂MoO₆/ZnO composite has a narrowed band gap and shows enhanced photocatalytic activity for methyl orange photo-decomposition under sunlight irradiation. This feature may broaden the application scope of Bi₂MoO₆/ZnO composite, for example as an efficient photocatalyst.