Preparation, characterization and enhanced visible-light photocatalytic activities of BiPO4/BiVO4 composites

Graphical abstract: - Highlights: • BiPO{sub 4}/BiVO{sub 4} composites were successfully prepared by the hydrothermal method. • BiPO{sub 4}/BiVO{sub 4} composites exhibited broad absorption in the visible region. • Visible-light photocatalytic activities of BiPO{sub 4}/BiVO{sub 4} composites were enhanced. • P/V molar ratio and pH value of the reaction affect photocatalytic activity. • The mechanism of enhanced visible-light photocatalytic activities was discussed. - Abstract: BiPO{sub 4}/BiVO{sub 4} composites with different P/V molar ratios were prepared by the hydrothermal method and the effect of pH values of hydrothermal reaction on photocatalytic activity of BiPO{sub 4}/BiVO{sub 4} composite was investigated. The photocatalysts were characterized by X-ray diffraction, field emission scanning electron microscopy, energy-dispersive spectroscopy, X-ray photoelectron spectroscopy and UV–vis diffuse reflectance spectroscopy. The photocatalytic property of BiPO{sub 4}/BiVO{sub 4} was evaluated by photocatalytic degradation of Methylene blue under visible light irradiation. The results showed that the photocatalytic activity of the composites was much higher than that of pure BiPO{sub 4} and BiVO{sub 4}. The rate constant of Methylene blue degradation over BiPO{sub 4}/BiVO{sub 4} (P/V molar ratio of 5:1 and hydrothermal reaction pH value of 1.5) is 1.7 times that of pure BiVO{sub 4}. The photocatalytic activity enhancement of BiPO{sub 4}/BiVO{sub 4}more » composite is closely related to the BiVO{sub 4} functioning as a sensitizer to adsorb visible light and the heterojunction of BiPO{sub 4}/BiVO{sub 4} acting as an active center for hindering the rapid recombination of electron–hole pairs during the photocatalytic reaction.« less