Fabrication of Ag3PO4/α-Bi2O3 composites with enhanced photocatalytic properties under visible light

The treatment of organic dyes is often conducted using the photocatalytic technique, however, the necessity for ultraviolet irradiation and efficient degradation still limit its wide practical application. Here, we report on a facile and effective co-precipitation hydrothermal method for fabricating Ag3PO4/alpha-Bi2O3 (AB) hierarchical heterostructures with an improved visible-light response. Rod-like alpha-Bi2O3 was firstly prepared under hydrothermal conditions, and then silver nitrate and disodium hydrogen phosphate were successively added to form AB. The measurement results signify that heterojunctions of polyhedral Ag3PO4 adhered to rod-like alpha-Bi2O3 were apparently found. AB possesses a markedly enhanced photocatalytic performance and outstanding ability in decomposing methylene blue (MB), methyl orange (MO) and rhodamine B (RhB) under visible light, compared to pure alpha-Bi2O3 or Ag3PO4. The amount of silver ions released reveals that the formation of alpha-Bi2O3 could enhance the stability of the AB composites. The fluorescence tests indicate that AB is helpful in producing the (OH)-O-center dot radicals responsible for enhanced photocatalytic activity. The degradation rate could be maintained even after three degradation cycles, suggesting an admirable chemical and physical stability of AB. In addition, a possible mechanism for the enhanced photocatalytic properties of AB was also discussed.