Visible light photocatalytic activity enhancement of Ag3PO4 dispersed on exfoliated bentonite for degradation of rhodamine B

To improve catalytic efficiency and reduce the amount of silver consumption, nanophase of silver phosphate was dispersed on an exfoliated bentonite (EB) to prepare the EB-Ag3PO4 photocatalyst. The as-synthesized samples were characterized by X-ray diffraction (XRD),Transmission electron microscopy (TEM), Fourier transform infrared spectroscopy (FTIR), Ultraviolet-vis (UV-vis) diffuse reflectance spectroscopy (DRS) and the Brunauer, Emmett, and Teller (BET) method. The composites were obtained with very fine nanoparticles of Ag3PO4 spread on the thin layers of exfoliated bentonite in order to improve the photocatalytic activity by exposing higher surface area of Ag3PO4. An optimized EB-Ag3PO4 composite showed much higher degradation of rhodamine B than that of the pure Ag3PO4 under visible light irradiation on a per mole basis of Ag3PO4. In addition, degradation efficiency of Ag3PO4 was apparently improved by compositing with exfoliated bentonite based on the kinetics of degradation data. The RhB degradation by EB-Ag3PO4-3 composite reached about 95% within 21 min under visible light irradiation, which is much higher than that of Ag3PO4 (82%). The results of improved photoactivity were mainly attributed to the electrostatic interaction between Ag3PO4 and negatively charged exfoliated bentonite, efficient migration of the photogenerated electrons and holes occurred in nanocomposite. This study reports a highly efficient and cost-effective photocatalyst for dye pollutant degradation and a potential photoelectric material. (C) 2015 Elsevier B.V. All rights reserved.