Oil-in-water self-assembled Ag[at]AgCl QDs sensitized Bi sub(2)WO sub(6): Enhanced photocatalytic degradation under visible light irradiation

• Published in: Applied catalysis. B, Environmental Environmental, 2015-03, Vol.164, p.192-203
• Main Authors: Liang, Yinghua, Lin, Shuanglong, Liu, Li, Hu, Jinshan, Cui, Wenquan
• Format: Article
• Language: English
• Subjects: Degradation; Light irradiation; Nanostructure; Photocatalysis; Photocatalysts; Scanning electron microscopy; Self assembly; Silver; Surface chemistry
• ISSN: 0926-3373
• DOI: 10.1016/j.apcatb.2014.08.048

Quantum dots (QDs) Ag[at]AgCl decorated on the surface of flower-like Bi sub(2)WO sub(6) (hereafter designated Ag[at]AgCl/Bi sub(2)WO sub(6)) were prepared via a facile oil-in-water self-assembly method. The photocatalysts were characterized by X-ray diffraction (XRD), Scanning electron microscopy (SEM), Transmission electron microscopy (TEM), UV-vis diffuse reflectance spectroscopy (DRS) and X-ray fluorescence spectrometer (XRF) etc. The characterization results indicated that QDs Ag[at]AgCl was observed to be evenly dispersed on the surface of BizWOe, and was approximately 10-20 nm in size. Ag[at]AgCl/Bi sub(2)WO sub(6) composites exhibited excellent UV-vis absorption, due to quantum dimension effect of Ag[at]AgCl QDs, the surface plasmonic resonance (SPR) of Ag nanopartides and the special flower-like structure of Bi sub(2)WO sub(6). The photo-electrochemical measurement verified that the suitable band potential of Ag[at]AgCl and Bi sub(2)WO sub(6) and the existence of metal Ag resulted in the high efficiency in charge separation of the composite. The photocatalytic activities of the Ag[at]AgCl/Bi sub(2)WO sub(6) samples were examined under visible light irradiation for the degradation of Rhodamine B (RhB). The composite presented excellent photocatalytic activity due to the synergetic effect of Bi sub(2)WO sub(6), AgCl, and Ag nanopartides. The Ag[at]AgCl(20 wt.%)/Bi sub(2)WO sub(6) sample exhibited the best photocatalytic activity, degrading 97.61% RhB after irradiation for 2 h, which was, respectively, 1.33 times and 1.32 times higher than that of Ag[at]AgCl and BizWOe photocatalyst. Meanwhile, phenol was degraded to further prove the degradation ability of Ag[at]AgCl/Bi sub(2)WO sub(6). Additionally, studies performed using radical scavengers indicated that O sub(2)-, h+ and Cl super(0) acted as the main reactive species. Based on above, a photocatalytic mechanism for organics degradation over Ag[at]AgCl/Bi sub(2)WO sub(6) was proposed.