Enhanced visible-light photocatalytic activity of Bi2WO6 nanoparticles by Ag2O cocatalyst

TLDR: In this paper, an Ag 2 O cocatalyst was applied on the surface of Bi 2 WO 6 nanoparticles by an impregnation method followed by a low-temperature treatment (100-350°C) and their performance was evaluated by the photocatalytic decolorization of methyl orange solution under visible light irradiation.

Abstract: Cocatalyst modification is an efficient strategy to improve the photocatalytic efficiency of photocatalysts by promoting the effective separation of photogenerated electrons and holes. However, most of the cocatalysts are restricted to noble metals (e.g., Ag, Au, Pt) and seldom investigation has been focused on their oxides. In this study, Ag 2 O cocatalyst was coated on the surface of Bi 2 WO 6 nanoparticles by an impregnation method followed by a low-temperature treatment (100–350 °C) and their photocatalytic performance was evaluated by the photocatalytic decolorization of methyl orange solution under visible-light irradiation. It was found that after the surface coating of Ag 2 O, the obtained Ag 2 O/Bi 2 WO 6 composites exhibited an obvious higher photocatalytic activity than the unmodified Bi 2 WO 6 nanoparticles and N-doped TiO 2 . Owing to the photosensitive property of pure Ag 2 O phase, the Ag–Ag 2 O composite easily formed during the decomposition process of organic substances under visible-light irradiation. On the bases of experimental result and band structure analysis, an Ag–Ag 2 O cocatalyst-enhanced photocatalytic mechanism is proposed; namely, the Ag–Ag 2 O cocatalyst possibly reduces oxygen via a multi-electron transfer mechanism. The present results suggest that Ag–Ag 2 O can act as a new and effective cocatalyst for the enhanced photocatalytic performance of photocatalysts, which provides a new approach for the design and development of high-performance visible-light photocatalysts.