Fabrication of BiOI/BiVO4 heterojunction with efficient visible-light-induced photocatalytic activity

• The excellent visible light absorption performance of BiVO4 and BiOI.
• The formation of p-BiOI/n-BiVO4 heterojunction.
• Efficient electron–hole separation;
• Enhanced visible light photocatalytic activity of BiOI/BiVO4.

For promoting the separation of electron–hole pairs and enhancing visible light photocatalytic activity, a novel visible-light-active BiOI/BiVO4 photocatalyst with a p–n heterojunction structure was prepared. The prepared photocatalyst was characterized by X-ray diffraction, transmission electron microscope, scanning electron microscopy, diffuse reflectance spectroscopy, and X-ray photoelectron spectrometer. The photocatalytic activity of the heterojunction was investigated by monitoring the change in methyl orange concentration under visible-light irradiation. The results reveal that the composite exhibited markedly improved efficiency for MO photodegradation in comparison with pure BiVO4 and BiOI. The degradation rate of BiOI/BiVO4 heterojunction was found to be 19.5 and 2.1 times higher than that of bare BiVO4 and BiOI, respectively. The enhanced photocatalytic activity is mainly attributed to the formation of BiOI/BiVO4 heterojunction that can facilitate the separation and transfer of the photogenerated charge carriers.