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: ∼21 nm) on the surface of Bi₂WO₆ microflowers (diameter: 2.5–4.5 μm) 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 > 400 nm). 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 0.0392 min⁻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.