Highly effective and stable Ag3PO4/WO3 photocatalysts for visible light degradation of organic dyes

The Ag3PO4/WO3 composites were prepared through a deposition-precipitation method and characterized by XRD, SEM, and DR UV-vis. These photocatalysts were evaluated in the degradation of rhodamine B (RhB) and methyl orange (MO) under visible light irradiation (lambda > 420 nm), and the synergistic effect of Ag3PO4 and WO3 was confirmed by notably higher photocatalytic activity compared to pure Ag3PO4 and WO3 catalysts. The effect of Ag3PO4:WO3 ratio on the catalytic activity was systemically studied and the catalyst AW(6/4) was found to exhibit the highest catalytic activity. The degradation rates of RhB and MO could reach up to 97% under visible light irradiation for 6 min and 35 min, respectively. Moreover, the Ag3PO4/WO3 photocatalysts showed higher recyclability than pure Ag3PO4 catalyst and could be recycled five runs in the degradation of RhB without any loss in the activity. The characterization of used catalysts proved that Ag3PO4 was effectively protected and much less metallic Ag was formed on the surface of Ag3PO4/WO3 catalyst. The improvement of photocatalytic activity and stability is mainly attributed to the highly effective separation of photogenerated electron-hole pairs and special transfer pathway of electrons and holes in Ag3PO4/WO3 composites. (C) 2014 Elsevier B.V. All rights reserved.