Facile synthesis of flower-like Ag3VO4/Bi2WO6 heterojunction with enhanced visible-light photocatalytic activity.

Constructing novel semiconductor heterojunctions is one of the most significant approaches to improving the photocatalytic performance of a photocatalyst. Herein, the Ag3VO4/Bi2WO6 heterojunction was prepared through in-situ anchoring Ag3VO4 nanoparticles (size: ∼21nm) on the surface of Bi2WO6 microflowers (diameter: 2.5-4.5μm) by a facile deposition route. The photocatalytic activity of these heterojunctions were studied by decomposing cationic dye rhodamine B (RhB), anionic dye methyl orange (MO) and neutral para-chlorophenol (4-CP) under visible light irradiation (λ>400nm). Among all the tested catalysts, the heterojunction with a Ag3VO4/Bi2WO6 molar ratio of 0.15/1 displays the maximum activity with the RhB degradation rate constant of up to 0.0392min-1, a 6.7 or 1.7 times more enhancement compared with the pure Bi2WO6 or Ag3VO4. It is found that the introduction of Ag3VO4 is in favor of suppressing the electron-hole pair recombination of Bi2WO6, leading to an enhanced photocatalytic activity with good stability. The photogenerated holes (h+) and superoxide radicals (O2-) play critical roles during the photocatalytic process. Ag3VO4/Bi2WO6 will have great potential in applications for environmental remediation due to the facile preparation method and superior photocatalytic activity.